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Merck Significantly Expands its Patient Assistance Program Offerings to Provide Access to More Medicines for People in Need
Survey shows more than one third of uninsured, unemployed Americans have skipped or incorrectly taken their prescribed medications to save money, yet many may qualify for free medicine
WHITEHOUSE STATION, N.J., Sep 22, 2010 (BUSINESS WIRE) -- Today, Merck announced that it has significantly expanded the number of Merck medicines available through its Merck Helps(TM) patient assistance programs, which include the Merck Patient Assistance Program, the Merck Vaccine Patient Assistance Program, the ACT Program for Oncology and Hepatitis C medicines, and the SUPPORT(R) Program for HIV/AIDS medicines. The Merck Helps programs provide Merck medicines and vaccines free of charge to eligible individuals, primarily the uninsured, who earn up to 400 percent of the federal poverty level who, without assistance, cannot afford needed Merck medicines.
To help increase awareness of all patient assistance programs, the Merck Company Foundation has provided a grant to NeedyMeds, a nonprofit organization with a mission to help people who cannot afford medicine or healthcare costs by making information about these programs available at no cost. NeedyMeds will be using the grant to translate its website into Spanish as well as working closely with various healthcare clinics to increase knowledge of and access to patient assistance programs.
"Merck has historically recognized the critical need for people to have access to the prescription medicines and vaccines they require, even if they lose their insurance," said Michael Rosenblatt, M.D., executive vice president and chief medical officer at Merck. "Our patient assistance programs now provide access to even more medicines for chronic conditions like asthma, diabetes and high blood pressure, allowing us to reach more people in need."
A recent telephone survey of more than 2,000 Americans, conducted by Harris Interactive on behalf of Merck(1), found that more than one third (35%) of those who are uninsured and unemployed did not buy or refill medicines they were prescribed, cut their dosage in half, or took expired medicine as a way to save money. Furthermore, while 32 percent of U.S. adults are potentially eligible for patient assistance programs, 79 percent of those who are uninsured and unemployed are somewhat or not at all aware that such programs exist.
"Unfortunately, many patients don't know that there are patient assistance programs available if they can't afford their prescriptions, and the need is great," said Richard Sagall, MD, co-founder of NeedyMeds. "That's why we are pleased to partner with Merck to help further raise awareness of these programs."
"With an uncertain economy and near double-digit unemployment, more patients are struggling to pay for their medicines than ever before," said Emmanuel Durham, director of Community Healthcare Network -- Helen B. Atkinson Health Center, New York, NY. "I have seen firsthand how the Merck Helps programs can keep needed medicines in reach."
About Merck Helps
For more than 50 years, Merck has helped millions of patients gain access to medicines for chronic conditions like asthma, diabetes and high blood pressure through the Merck Patient Assistance Program. As a global healthcare leader working to help the world be well, Merck provides its medicines and adult vaccines for free to people who do not have prescription drug or health insurance coverage and qualify for a Merck Helps program. Merck Helps programs include:
-- The Merck Patient Assistance Program, which helps eligible patients who earn up to 400 percent of the federal poverty level gain access to Merck medicines for chronic conditions like asthma and diabetes.
-- The Merck Vaccine Patient Assistance Program, which provides free vaccines to adults over age 19 who do not have health insurance coverage for vaccines and who earn up to 400 percent of the federal poverty level.
-- The ACT Program for Oncology and Hepatitis C medicines, which provides free reimbursement support services and refers appropriate patients to a patient assistance program for eligible individuals who earn up to 500 percent of the federal poverty level.
-- The SUPPORTProgram for HIV/AIDS, which provides free reimbursement support services and refers appropriate patients to a patient assistance program for eligible individuals who earn up to 500 percent of the federal poverty level.
All Merck Helps programs are confidential and patients may qualify for the Merck Patient Assistance Program and the Merck Vaccine Patient Assistance Program if they have a household income of $43,320 or less for individuals, $58,280 or less for couples, or $88,200 or less for a family of four, even if the financial situation is temporary due to unemployment or other reasons. Patients may qualify for The ACT Program and the SUPPORT Program if they have a household income of $54,150 or less for individuals, $72,800 or less for couples, or $110,250 or less for a family of four. With the Merck Helps programs, there are no application fees, no co-payments and a simple enrollment process. Many medicines can be delivered to a patient's home or doctor's office at no charge. Patients in need of information should visit www.MerckHelps.com or call (800) PAP-5400.
About NeedyMeds
NeedyMeds is a non-profit organization founded in 1997 as a resource for people who need help with the cost of medicine. The mission of NeedyMeds has been, since its inception, to make comprehensive and reliable information about assistance programs available to low-income patients and their advocates at no cost. NeedyMeds' website is visited by over 14,000 people each workday.
About Merck
Today's Merck is a global healthcare leader working to help the world be well. Merck is known as MSD outside the United States and Canada. Through our prescription medicines, vaccines, biologic therapies, and consumer care and animal health products, we work with customers and operate in more than 140 countries to deliver innovative health solutions. We also demonstrate our commitment to increasing access to healthcare through far-reaching policies, programs and partnerships. For more information, visit www.merck.com.
(1) This telephone survey was conducted by Harris Interactive on behalf of Merck from August 20 to 23, 2010 among 2,012 U.S. adults of whom 549 do not have any prescription drug benefits and 131 do not have any prescription drug benefits and are not employed.
SOURCE: Merck
Media Contact:
Merck
Ron Rogers, 908-423-6449
Monday, September 27, 2010
Mistakes in Genotyping 1, which may occur more in IDUs, becomes more important now with resistance a concern associated with new HCV oral drugs
Mistakes in Genotyping 1, which may occur more in IDUs, becomes more important now with resistance a concern associated with new HCV oral drugs, activity & development of resistance appears to perhaps differ between genotypes 1a and 1b, as well mistakes in genotyping 1 vs 2 or 3 appears to occur
Evaluation of Versant Hepatitis C Virus Genotype Assay (LiPA) 2.0 - pdf attached - (09/21/10)
Concerns About HCV Genotyping: Hepatitis C Virus (HCV) Genotype 1 Subtype Identification in New HCV Drug Development and Future Clinical Practice - pdf attached - (09/20/10)
Methods based on the sole analysis of the 5'NCR, namely Trugene HCV Genotyping Kit and INNO-LiPA HCV 1.0, failed to correctly identify HCV subtype 1a in 22.8% and 29.5% of cases, and HCV subtype 1b in 9.5% and 8.7% of cases, respectively (Table 1)...... The results clearly show that, although they are by far the most widely used techniques in new HCV drug development trials, genotyping techniques based on the sole analysis of the 5'NCR should be avoided, as they mistype approximately 25% and 10% of HCV subtype 1a and 1b strains, respectively......INNO-LiPA HCV 2.0 displays the same 5'NCR oligonucleotide probes as INNO-LiPA HCV 1.0, plus core-encoded oligonucleotide probes aimed at better discriminating between HCV subtypes 1a and 1b. With INNO-LiPA HCV 2.0, subtype identification was corrected in 64 of the 70 subtypes 1a that were incorrectly typed with INNO-LiPA HCV 1.0. Five samples could not be PCR-amplified in the core-coding region and the result was not interpretable with INNO-LiPA HCV 2.0 in the remaining case (Table 1). INNO-LiPA HCV 2.0 also corrected subtype identification in 13 of 23 subtypes 1b that were incorrectly typed with INNO-LiPA HCV 1.0. Eight samples could not be PCR-amplified in the core-coding region and the result was not interpretable with INNO-LiPA HCV 2.0 in the remaining two cases (Table 1). Overall, the second-generation line probe assay correctly classified 97.5% of subtype 1a and 96.2% of subtype 1b strains. When only samples that could be PCR-amplified with the assay procedure were taken into account, correct subtype determination was achieved in 99.6% and 99.2% of cases, respectively (Table 1)The real-time PCR-based assay targeting both the 5'NCR and the NS5B region, Abbott RealTime HCV Genotype II assay, correctly identified 93.2% of subtype 1a and 88.9% of subtype 1b strains. Only 2 HCV subtype 1b samples could not be PCR-amplified with this method (Table 1)......Novel assays have been recently developed that aim at better discriminating among the different HCV genotype 1 subtypes and between genotypes 1 and 6. Abbott RealTime HCV Genotype II assay is a real-time PCR method using several sets of genotype- and subtype-specific primers and probes located in both the 5'NCR and the NS5B-coding region. As shown in Table 1, adding a second target region for analysis led to substantially improving HCV genotype 1 subtype identification compared to methods targeting the sole 5'NCR. However, in contrast with a previous report [33], we found that this assay failed to correctly identify HCV genotype 1 subtype in approximately 10% of cases"
Evaluation of Versant Hepatitis C Virus Genotype Assay (LiPA) 2.0 - pdf attached - (09/21/10)
Concerns About HCV Genotyping: Hepatitis C Virus (HCV) Genotype 1 Subtype Identification in New HCV Drug Development and Future Clinical Practice - pdf attached - (09/20/10)
Methods based on the sole analysis of the 5'NCR, namely Trugene HCV Genotyping Kit and INNO-LiPA HCV 1.0, failed to correctly identify HCV subtype 1a in 22.8% and 29.5% of cases, and HCV subtype 1b in 9.5% and 8.7% of cases, respectively (Table 1)...... The results clearly show that, although they are by far the most widely used techniques in new HCV drug development trials, genotyping techniques based on the sole analysis of the 5'NCR should be avoided, as they mistype approximately 25% and 10% of HCV subtype 1a and 1b strains, respectively......INNO-LiPA HCV 2.0 displays the same 5'NCR oligonucleotide probes as INNO-LiPA HCV 1.0, plus core-encoded oligonucleotide probes aimed at better discriminating between HCV subtypes 1a and 1b. With INNO-LiPA HCV 2.0, subtype identification was corrected in 64 of the 70 subtypes 1a that were incorrectly typed with INNO-LiPA HCV 1.0. Five samples could not be PCR-amplified in the core-coding region and the result was not interpretable with INNO-LiPA HCV 2.0 in the remaining case (Table 1). INNO-LiPA HCV 2.0 also corrected subtype identification in 13 of 23 subtypes 1b that were incorrectly typed with INNO-LiPA HCV 1.0. Eight samples could not be PCR-amplified in the core-coding region and the result was not interpretable with INNO-LiPA HCV 2.0 in the remaining two cases (Table 1). Overall, the second-generation line probe assay correctly classified 97.5% of subtype 1a and 96.2% of subtype 1b strains. When only samples that could be PCR-amplified with the assay procedure were taken into account, correct subtype determination was achieved in 99.6% and 99.2% of cases, respectively (Table 1)The real-time PCR-based assay targeting both the 5'NCR and the NS5B region, Abbott RealTime HCV Genotype II assay, correctly identified 93.2% of subtype 1a and 88.9% of subtype 1b strains. Only 2 HCV subtype 1b samples could not be PCR-amplified with this method (Table 1)......Novel assays have been recently developed that aim at better discriminating among the different HCV genotype 1 subtypes and between genotypes 1 and 6. Abbott RealTime HCV Genotype II assay is a real-time PCR method using several sets of genotype- and subtype-specific primers and probes located in both the 5'NCR and the NS5B-coding region. As shown in Table 1, adding a second target region for analysis led to substantially improving HCV genotype 1 subtype identification compared to methods targeting the sole 5'NCR. However, in contrast with a previous report [33], we found that this assay failed to correctly identify HCV genotype 1 subtype in approximately 10% of cases"
Santaris Pharma A/S Advances miravirsen, the First microRNA-Targeted Drug to Enter Clinical Trials
Santaris Pharma A/S Advances miravirsen, the First microRNA-Targeted Drug to Enter Clinical Trials, Into Phase 2 to Treat Patients Infected With Hepatitis C Virus
- Santaris Pharma A/S initiates Phase 2a clinical trial with miravirsen (SPC3649) to assess safety and tolerability in treatment-naive patients with chronic Hepatitis C
By: PR Newswire
Sep. 22, 2010 07:15 AM
Therapeutic Silencing of MicroRNA-122 by SPC3649 in Primates with ...
Science Mag, Dec 3, 2009 ... Here, we investigated the potential of miR-122 antagonism by SPC3649 as ... We next assessed the in vivo antagonism of miR-122 in chimpanzee ...
www.natap.org/2009/HCV/011009_01.htm
HOERSHOLM, Denmark and SAN DIEGO, September 22, 2010 /PRNewswire/ -- Santaris Pharma A/S, a clinical-stage biopharmaceutical company focused on the discovery and development of RNA-targeted therapies, today announced that it has advanced miravirsen (SPC3649), the first microRNA-targeted drug to enter clinical trials, into Phase 2 studies to assess the safety and tolerability of the drug in treatment-naive patients infected with the Hepatitis C virus (HCV).
Paving the way to conduct the first clinical trials of a microRNA-targeted drug in the United States, Santaris Pharma A/S also received acceptance of its Investigational New Drug (IND) application from the U.S. Food and Drug Administration (FDA). In addition to the United States, the Phase 2a clinical trials will be conducted in the Netherlands, Germany, Poland, Romania, and Slovakia.
The World Health Organization estimates about 3% of the world's population has been infected with HCV and that some 170 million are chronic carriers at risk of developing liver cirrhosis and/or liver cancer(2). Approximately 3-4 million Americans are chronically infected with an estimated 40,000 new infections per year(1). In Europe, there are about 4 million carriers(2). The current standard of care, pegylated interferon in combination with ribavirin, is effective in only about 50% of those treated(1).
Developed using Santaris Pharma A/S proprietary Locked Nucleic Acid (LNA) Drug Platform, miravirsen is a specific inhibitor of miR-122, a liver specific microRNA that the Hepatitis C virus requires for replication. Miravirsen is designed to recognize and sequester miR-122, making it unavailable to the Hepatitis C virus. As a result, the replication of the virus is effectively inhibited and the level of Hepatitis C virus is reduced.
"Advancing miravirsen, the first microRNA-targeted drug to enter clinical trials, into Phase 2 studies in patients with Hepatitis C demonstrates Santaris Pharma A/S leadership in developing RNA-targeted medicines," said Arthur A. Levin, Ph.D., Vice President, Chief Development Officer and President, US Operations. "Receiving IND acceptance from the FDA to conduct the first clinical trials with a microRNA-targeted drug in the United States brings Santaris Pharma A/S one step closer to potentially providing a growing number of patients chronically infected with HCV with a more effective and better tolerated treatment option."
The LNA Drug Platform is the only technology with both mRNA and microRNA targeted drugs in clinical trials, reinforcing the broad utility of the platform. The unique combination of small size and very high affinity, which is only achievable with LNA-based drugs, allows this new class of drugs to potently and specifically inhibit RNA targets in many different tissues without the need for complex delivery vehicles. LNA-based drugs are a promising new type of therapy that enables scientists to develop drugs to attack previously inaccessible pathways.
"Using our LNA Drug Platform to advance the first microRNA-targeted therapy into human clinical trials was certainly a scientific breakthrough," said Henrik Oerum, Ph.D., Vice President and Chief Scientific Officer of Santaris Pharma A/S. "We are extremely pleased with the results of the Phase I trials and excited to progress miravirsen into Phase 2 clinical trials. Because of its unique mechanism of action and tolerability profile, miravirsen has the potential to be an effective treatment option for patients with HCV."
The randomized, double-blind, placebo-controlled, ascending multiple-dose Phase 2a study will assess the safety and tolerability of miravirsen and is designed to enroll up to 55 treatment-naïve patients with chronic Hepatitis C virus genotype 1 infection. Secondary endpoints include pharmacokinetics of miravirsen and its effect on viral load. Miravirsen will be given as subcutaneous injections weekly or every other week for four weeks.
Data from Phase 1 clinical studies with miravirsen in healthy volunteers show that the drug is well tolerated. A recent study published in Science demonstrated that miravirsen successfully inhibited miR-122 and dramatically reduced Hepatitis C virus in the liver and in the bloodstream in chimpanzees chronically infected with the Hepatitis C virus(3). Miravirsen provided continued efficacy in the animals up to several months after the treatment period with no adverse events and no evidence of viral rebound or resistance.
In addition to miravirsen, Santaris Pharma A/S has a robust product pipeline targeting mRNAs and microRNAs both internally as well as in partnerships and collaborations with miRagen Therapeutics (cardiovascular diseases), Shire plc (rare genetic disorders), Pfizer (undisclosed therapeutic areas), GlaxoSmithKline (viral disease) and Enzon Pharmaceuticals (oncology).
About microRNAs
MicroRNAs have emerged as an important class of small RNAs encoded in the genome. They act to control the expression of sets of genes and entire pathways and are thus thought of as master regulators of gene expression. Recent studies have demonstrated that microRNAs are associated with many disease processes. Because they are single molecular entities that dictate the expression of fundamental regulatory pathways, microRNAs represent potential drug targets for controlling many biologic and disease processes.
About Locked Nucleic Acid (LNA) Drug Platform
The LNA Drug Platform and Drug Discovery Engine developed by Santaris Pharma A/S combines the Company's proprietary LNA chemistry with its highly specialized and targeted drug development capabilities to rapidly deliver potent single-stranded LNA-based drug candidates against RNA targets, both mRNA and microRNA, for a range of diseases including metabolic disorders, infectious and inflammatory diseases, cancer and rare genetic disorders. The LNA Drug Platform overcomes the limitations of earlier antisense and siRNA technologies to deliver potent single-stranded LNA-based drug candidates across a multitude of disease states. The unique combination of small size and very high affinity, which is only achievable with LNA-based drugs, allows this new class of drugs to potently and specifically inhibit RNA targets in many different tissues without the need for complex delivery vehicles. LNA-based drugs are a promising new type of therapy that enables scientists to develop drugs to attack previously inaccessible clinical pathways. The most important features of LNA-based drugs include excellent specificity, providing optimal targeting; increased affinity to targets providing improved potency; and strong pharmacology upon systemic delivery without complicated delivery vehicles.
About Santaris Pharma A/S
Santaris Pharma A/S is a privately held clinical-stage biopharmaceutical company focused on the discovery and development of RNA-targeted therapies. The Locked Nucleic Acid (LNA) Drug Platform and Drug Discovery Engine developed by Santaris Pharma A/S combine the Company's proprietary LNA chemistry with its highly specialized and targeted drug development capabilities to rapidly deliver potent single-stranded LNA-based drug candidates across a multitude of disease states. The Company's research and development activities focus on infectious diseases and metabolic disorders, while partnerships with major pharmaceutical companies include a range of therapeutic areas including cancer, cardiovascular disease, infectious and inflammatory diseases, and rare genetic disorders. The Company has strategic partnerships with miRagen Therapeutics, Shire plc, Pfizer, GlaxoSmithKline, and Enzon Pharmaceuticals. As part of its broad patent estate, the Company holds exclusive worldwide rights to all therapeutic uses of LNA. Santaris Pharma A/S, founded in 2003, is headquartered in Denmark with operations in the United States. Please visit http://www.santaris.com for more information.
(1) American Association for the Study of Liver Diseases -
http://www.aasld.org/patients/Pages/LiverFastFactsHepC.aspx
(2) World Health Organization -
http://www.who.int/csr/disease/hepatitis/Hepc.pdf
(3) Science. 2010 Jan 8; 327(5962):198-201. Epub 2009 Dec 3
- Santaris Pharma A/S initiates Phase 2a clinical trial with miravirsen (SPC3649) to assess safety and tolerability in treatment-naive patients with chronic Hepatitis C
By: PR Newswire
Sep. 22, 2010 07:15 AM
Therapeutic Silencing of MicroRNA-122 by SPC3649 in Primates with ...
Science Mag, Dec 3, 2009 ... Here, we investigated the potential of miR-122 antagonism by SPC3649 as ... We next assessed the in vivo antagonism of miR-122 in chimpanzee ...
www.natap.org/2009/HCV/011009_01.htm
HOERSHOLM, Denmark and SAN DIEGO, September 22, 2010 /PRNewswire/ -- Santaris Pharma A/S, a clinical-stage biopharmaceutical company focused on the discovery and development of RNA-targeted therapies, today announced that it has advanced miravirsen (SPC3649), the first microRNA-targeted drug to enter clinical trials, into Phase 2 studies to assess the safety and tolerability of the drug in treatment-naive patients infected with the Hepatitis C virus (HCV).
Paving the way to conduct the first clinical trials of a microRNA-targeted drug in the United States, Santaris Pharma A/S also received acceptance of its Investigational New Drug (IND) application from the U.S. Food and Drug Administration (FDA). In addition to the United States, the Phase 2a clinical trials will be conducted in the Netherlands, Germany, Poland, Romania, and Slovakia.
The World Health Organization estimates about 3% of the world's population has been infected with HCV and that some 170 million are chronic carriers at risk of developing liver cirrhosis and/or liver cancer(2). Approximately 3-4 million Americans are chronically infected with an estimated 40,000 new infections per year(1). In Europe, there are about 4 million carriers(2). The current standard of care, pegylated interferon in combination with ribavirin, is effective in only about 50% of those treated(1).
Developed using Santaris Pharma A/S proprietary Locked Nucleic Acid (LNA) Drug Platform, miravirsen is a specific inhibitor of miR-122, a liver specific microRNA that the Hepatitis C virus requires for replication. Miravirsen is designed to recognize and sequester miR-122, making it unavailable to the Hepatitis C virus. As a result, the replication of the virus is effectively inhibited and the level of Hepatitis C virus is reduced.
"Advancing miravirsen, the first microRNA-targeted drug to enter clinical trials, into Phase 2 studies in patients with Hepatitis C demonstrates Santaris Pharma A/S leadership in developing RNA-targeted medicines," said Arthur A. Levin, Ph.D., Vice President, Chief Development Officer and President, US Operations. "Receiving IND acceptance from the FDA to conduct the first clinical trials with a microRNA-targeted drug in the United States brings Santaris Pharma A/S one step closer to potentially providing a growing number of patients chronically infected with HCV with a more effective and better tolerated treatment option."
The LNA Drug Platform is the only technology with both mRNA and microRNA targeted drugs in clinical trials, reinforcing the broad utility of the platform. The unique combination of small size and very high affinity, which is only achievable with LNA-based drugs, allows this new class of drugs to potently and specifically inhibit RNA targets in many different tissues without the need for complex delivery vehicles. LNA-based drugs are a promising new type of therapy that enables scientists to develop drugs to attack previously inaccessible pathways.
"Using our LNA Drug Platform to advance the first microRNA-targeted therapy into human clinical trials was certainly a scientific breakthrough," said Henrik Oerum, Ph.D., Vice President and Chief Scientific Officer of Santaris Pharma A/S. "We are extremely pleased with the results of the Phase I trials and excited to progress miravirsen into Phase 2 clinical trials. Because of its unique mechanism of action and tolerability profile, miravirsen has the potential to be an effective treatment option for patients with HCV."
The randomized, double-blind, placebo-controlled, ascending multiple-dose Phase 2a study will assess the safety and tolerability of miravirsen and is designed to enroll up to 55 treatment-naïve patients with chronic Hepatitis C virus genotype 1 infection. Secondary endpoints include pharmacokinetics of miravirsen and its effect on viral load. Miravirsen will be given as subcutaneous injections weekly or every other week for four weeks.
Data from Phase 1 clinical studies with miravirsen in healthy volunteers show that the drug is well tolerated. A recent study published in Science demonstrated that miravirsen successfully inhibited miR-122 and dramatically reduced Hepatitis C virus in the liver and in the bloodstream in chimpanzees chronically infected with the Hepatitis C virus(3). Miravirsen provided continued efficacy in the animals up to several months after the treatment period with no adverse events and no evidence of viral rebound or resistance.
In addition to miravirsen, Santaris Pharma A/S has a robust product pipeline targeting mRNAs and microRNAs both internally as well as in partnerships and collaborations with miRagen Therapeutics (cardiovascular diseases), Shire plc (rare genetic disorders), Pfizer (undisclosed therapeutic areas), GlaxoSmithKline (viral disease) and Enzon Pharmaceuticals (oncology).
About microRNAs
MicroRNAs have emerged as an important class of small RNAs encoded in the genome. They act to control the expression of sets of genes and entire pathways and are thus thought of as master regulators of gene expression. Recent studies have demonstrated that microRNAs are associated with many disease processes. Because they are single molecular entities that dictate the expression of fundamental regulatory pathways, microRNAs represent potential drug targets for controlling many biologic and disease processes.
About Locked Nucleic Acid (LNA) Drug Platform
The LNA Drug Platform and Drug Discovery Engine developed by Santaris Pharma A/S combines the Company's proprietary LNA chemistry with its highly specialized and targeted drug development capabilities to rapidly deliver potent single-stranded LNA-based drug candidates against RNA targets, both mRNA and microRNA, for a range of diseases including metabolic disorders, infectious and inflammatory diseases, cancer and rare genetic disorders. The LNA Drug Platform overcomes the limitations of earlier antisense and siRNA technologies to deliver potent single-stranded LNA-based drug candidates across a multitude of disease states. The unique combination of small size and very high affinity, which is only achievable with LNA-based drugs, allows this new class of drugs to potently and specifically inhibit RNA targets in many different tissues without the need for complex delivery vehicles. LNA-based drugs are a promising new type of therapy that enables scientists to develop drugs to attack previously inaccessible clinical pathways. The most important features of LNA-based drugs include excellent specificity, providing optimal targeting; increased affinity to targets providing improved potency; and strong pharmacology upon systemic delivery without complicated delivery vehicles.
About Santaris Pharma A/S
Santaris Pharma A/S is a privately held clinical-stage biopharmaceutical company focused on the discovery and development of RNA-targeted therapies. The Locked Nucleic Acid (LNA) Drug Platform and Drug Discovery Engine developed by Santaris Pharma A/S combine the Company's proprietary LNA chemistry with its highly specialized and targeted drug development capabilities to rapidly deliver potent single-stranded LNA-based drug candidates across a multitude of disease states. The Company's research and development activities focus on infectious diseases and metabolic disorders, while partnerships with major pharmaceutical companies include a range of therapeutic areas including cancer, cardiovascular disease, infectious and inflammatory diseases, and rare genetic disorders. The Company has strategic partnerships with miRagen Therapeutics, Shire plc, Pfizer, GlaxoSmithKline, and Enzon Pharmaceuticals. As part of its broad patent estate, the Company holds exclusive worldwide rights to all therapeutic uses of LNA. Santaris Pharma A/S, founded in 2003, is headquartered in Denmark with operations in the United States. Please visit http://www.santaris.com for more information.
(1) American Association for the Study of Liver Diseases -
http://www.aasld.org/patients/Pages/LiverFastFactsHepC.aspx
(2) World Health Organization -
http://www.who.int/csr/disease/hepatitis/Hepc.pdf
(3) Science. 2010 Jan 8; 327(5962):198-201. Epub 2009 Dec 3
HCV: Health Danger of Parties Past
HCV: Health Danger of Parties Past
Wall Street Journal
Sept 20 2010
Most people think their wild-child past is just that—in the past. But some former party animals may be carrying a harmful reminder of their youth and not know it.
People who used intravenous drugs, snorted cocaine with a shared straw, or had an unsterile tattoo or body piercing could be infected with hepatitis C and not realize it. The virus, which spreads via blood-to-blood contact, can cause no symptoms for decades while silently destroying the liver.
Some people may have innocently been infected if they had a blood transfusion before 1992, when the blood supply began to be screened for the virus. Others may have contracted the virus simply by sharing a toothbrush or a razor. More than three million Americans have been diagnosed with hep C, and health experts say at least that many more are unaware that they have it.
"There's a huge reservoir of people who made a few bad decisions many years ago. Now they're successful business people, lawyers, doctors, school principals, and they don't know they are carrying this," says Joseph Galati, medical director of the Center for Liver Disease and Transplantation at Houston's Methodist Hospital. In the meantime, he says, "they could be doing things like drinking alcohol that accelerate the disease or transmitting it to other people."
Hep C, first identified in 1989, is today the leading reason for liver transplants and causes about 12,000 deaths in the U.S. each year. In most cases, the infection becomes chronic, inflaming the liver for years, but often with no apparent symptoms unless the inflammation becomes severe. In about 20% of cases, it progresses to cirrhosis, a severe scarring that shuts down liver function. And about 20% of those cirrhosis cases become liver cancer.
About 20,000 people are diagnosed with hepatitis C each year, and some two-thirds of those are middle-aged, having contracted the disease 20 or 30 years ago.
There is no vaccine against hep C, unlike for hepatitis A and B, which are liver diseases caused by different viruses. Hep C can be cured with a year-long course of chemotherapy drugs, but only about 50% of patients respond to them. A host of new medications now in clinical trials could work faster, and raise the cure rate as high as 80%, according to early results.
Hep C can be diagnosed with an inexpensive blood test that checks for antibodies—if doctors think to look for it. If that test is positive, another test can determine if the virus is still active. (In about 15% of hep C cases, the virus goes away on its own, although the antibodies may still be present.)
A regular annual checkup may reveal elevated liver enzymes. But many people with hep C have normal enzyme levels, and only vague symptoms like fatigue or joint pain, until the damage is well advanced.
"I never had any symptoms. I've had major surgery twice and nobody picked up on this," says a Houston nurse who was diagnosed with hep C in December at age 59. She thinks she was exposed to the virus in 1980, when she was accidentally stuck with a needle while caring for a patient. Her hep C was only found because a new job required the test for hep C antibodies. By then, 35% of her liver was damaged from cirrhosis. She is currently undergoing treatment in a clinical trial with Dr. Galati.
Even minute blood drops—from borrowing a toothbrush or piercing several friends' ears with the same needle—can transmit the virus. "Any blood-to-blood transition route can spread it, no matter how microscopic," says Melissa Palmer, medical director at New York University's Hepatology Associates in Plainview, NY.
"People may have done something once and forgotten about it, like share a $1 or a $100 bill to snort cocaine. The blood vessels in the nose are very weak and could bleed a little, and then the blood gets passed to the next person," says Dr. Palmer.
For now, the standard course of treatment for hep C is two chemotherapy drugs—interferon in weekly injections and ribavirin as pills three times a day—for either 24 or 48 weeks, an arduous regime that can cost more than $50,000 a year. Side effects can include fatigue, weakness, muscle and joint pain, hair loss, nausea and depression. Some patients need additional drugs to boost their red and white blood cells, which the chemo drugs deplete. Some have to stop the treatment because it can be so debilitating.
----------------------------------
Hepatitis A Through E
Hepatitis is an inflammation of the liver, generally caused by viruses, with symptoms ranging from slight to severe. Versions A through C are the most common.
* Hep A: Transmitted via contaminated water or food, particularly in countries with poor hygiene. Symptoms include fatigue, fever, abdominal pain, depression and jaundice. Permanent liver damage is rare. Vaccine recommended for all children at 1 year.
* Hep B: Two billion people world-wide have been infected with hep B, mostly through infected blood or body fluids. It can become chronic and lead to cirrhosis and liver cancer, but most adults clear the virus without treatment and are then immune. Vaccination is now required for many college students and healthcare workers.
* Hep C: Spread by blood-to-blood transmission, with few symptoms either in early stages or for decades later. About 20% of chronic cases develop into cirrhosis or liver cancer. Curable in about 50% of cases by chemotherapy.
* Hep D: Caused by a small RNA virus that only propagates in the presence of hep B, greatly increasing the chance of cancer, cirrhosis and death. Hep B vaccine will prevent illness from D.
* Hep E: Transmitted by fecal-oral contamination in unsanitary conditions. Patients are generally very ill for the first few weeks of infection then the virus usually clears on it own. Vaccine is being tested.
Source: WSJ Reporting
---------------------------------------
"I was really, really sick for a while—I had to hide under the wedding gowns so I could nap," says Sidney Merry, 53, who works for a bridal retailer in Houston. Routine blood tests spotted her hep C, which she thinks she got from a blood transfusion in the 1970s, and later started treatment with Dr. Galati. Ms. Merry stuck with the program and is now free of the virus. She helps counsel other patients undergoing treatment.
Ms. Merry says two of her friends died of hep C they declined to treat, and her own mother died of liver cancer at age 53, from what Ms. Merry suspects may also have been hep C. "This touches many lives—but it's so unspoken about and misunderstood," she says.
Two new drugs on the horizon—boceprevir by Merck & Co. and telaprevir by Vertex Pharmaceuticals Inc.—are protease inhibitors similar to those in AIDS drugs. They could win approval by the Food and Drug Administration next year. Other companies are studying different approaches to fight hep C.
In July, the FDA approved a synthetic form of interferon, called Infergen, by Three Rivers Pharmaceuticals LLC, for use in daily injections for patients who don't respond to the first course of treatment.
In some cases, doctors are advising hep C patients to postpone treatment until the new drugs come on the market. But Dr. Galati, who has been the principal investigator for several industry-sponsored clinical trials, notes that the new drugs will be in addition to the current ones, so waiting for the new regimes won't allow patients to avoid the side effects.
Unborn babies can acquire hep C from infected mothers. Kathryn Maloney had complained of fatigue for years before she was diagnosed with hep C in 2005. "Turns out I had it my whole life and didn't know," says Ms. Maloney, 29, an accountant in Houston.
Since there was no obvious source of her infection, Dr. Galati suggested that her mother, Pamela Grant, be tested too. She tested positive as well, though she has no idea when or where she was exposed. She and her daughter underwent treatment together. They also took part in a clinical trial for one of the new medications and are now free of the virus.
Some patients opt to forgo treatment, since only about 20% progress to cirrhosis. But doctors can't tell in advance which cases will progress. Meanwhile, drinking alcohol, smoking cigarettes and carrying excess weight make cirrhosis more likely.
Some health experts are urging that the general public be screened for hep C; the blood test for antibodies costs only about $12. Short of that, liver specialists urge anyone who might have been exposed, no matter how or how long ago or how well they feel now, to tell their doctors and be tested.
Since hep C can carry a lingering stigma of past drug use, even though there are many other ways to contract it, Dr. Galati says some primary-care physicians routinely hand patients a list of risk factors and say, "If you fit into any of these categories, you should get tested. You don't need to tell me which one."
Wall Street Journal
Sept 20 2010
Most people think their wild-child past is just that—in the past. But some former party animals may be carrying a harmful reminder of their youth and not know it.
People who used intravenous drugs, snorted cocaine with a shared straw, or had an unsterile tattoo or body piercing could be infected with hepatitis C and not realize it. The virus, which spreads via blood-to-blood contact, can cause no symptoms for decades while silently destroying the liver.
Some people may have innocently been infected if they had a blood transfusion before 1992, when the blood supply began to be screened for the virus. Others may have contracted the virus simply by sharing a toothbrush or a razor. More than three million Americans have been diagnosed with hep C, and health experts say at least that many more are unaware that they have it.
"There's a huge reservoir of people who made a few bad decisions many years ago. Now they're successful business people, lawyers, doctors, school principals, and they don't know they are carrying this," says Joseph Galati, medical director of the Center for Liver Disease and Transplantation at Houston's Methodist Hospital. In the meantime, he says, "they could be doing things like drinking alcohol that accelerate the disease or transmitting it to other people."
Hep C, first identified in 1989, is today the leading reason for liver transplants and causes about 12,000 deaths in the U.S. each year. In most cases, the infection becomes chronic, inflaming the liver for years, but often with no apparent symptoms unless the inflammation becomes severe. In about 20% of cases, it progresses to cirrhosis, a severe scarring that shuts down liver function. And about 20% of those cirrhosis cases become liver cancer.
About 20,000 people are diagnosed with hepatitis C each year, and some two-thirds of those are middle-aged, having contracted the disease 20 or 30 years ago.
There is no vaccine against hep C, unlike for hepatitis A and B, which are liver diseases caused by different viruses. Hep C can be cured with a year-long course of chemotherapy drugs, but only about 50% of patients respond to them. A host of new medications now in clinical trials could work faster, and raise the cure rate as high as 80%, according to early results.
Hep C can be diagnosed with an inexpensive blood test that checks for antibodies—if doctors think to look for it. If that test is positive, another test can determine if the virus is still active. (In about 15% of hep C cases, the virus goes away on its own, although the antibodies may still be present.)
A regular annual checkup may reveal elevated liver enzymes. But many people with hep C have normal enzyme levels, and only vague symptoms like fatigue or joint pain, until the damage is well advanced.
"I never had any symptoms. I've had major surgery twice and nobody picked up on this," says a Houston nurse who was diagnosed with hep C in December at age 59. She thinks she was exposed to the virus in 1980, when she was accidentally stuck with a needle while caring for a patient. Her hep C was only found because a new job required the test for hep C antibodies. By then, 35% of her liver was damaged from cirrhosis. She is currently undergoing treatment in a clinical trial with Dr. Galati.
Even minute blood drops—from borrowing a toothbrush or piercing several friends' ears with the same needle—can transmit the virus. "Any blood-to-blood transition route can spread it, no matter how microscopic," says Melissa Palmer, medical director at New York University's Hepatology Associates in Plainview, NY.
"People may have done something once and forgotten about it, like share a $1 or a $100 bill to snort cocaine. The blood vessels in the nose are very weak and could bleed a little, and then the blood gets passed to the next person," says Dr. Palmer.
For now, the standard course of treatment for hep C is two chemotherapy drugs—interferon in weekly injections and ribavirin as pills three times a day—for either 24 or 48 weeks, an arduous regime that can cost more than $50,000 a year. Side effects can include fatigue, weakness, muscle and joint pain, hair loss, nausea and depression. Some patients need additional drugs to boost their red and white blood cells, which the chemo drugs deplete. Some have to stop the treatment because it can be so debilitating.
----------------------------------
Hepatitis A Through E
Hepatitis is an inflammation of the liver, generally caused by viruses, with symptoms ranging from slight to severe. Versions A through C are the most common.
* Hep A: Transmitted via contaminated water or food, particularly in countries with poor hygiene. Symptoms include fatigue, fever, abdominal pain, depression and jaundice. Permanent liver damage is rare. Vaccine recommended for all children at 1 year.
* Hep B: Two billion people world-wide have been infected with hep B, mostly through infected blood or body fluids. It can become chronic and lead to cirrhosis and liver cancer, but most adults clear the virus without treatment and are then immune. Vaccination is now required for many college students and healthcare workers.
* Hep C: Spread by blood-to-blood transmission, with few symptoms either in early stages or for decades later. About 20% of chronic cases develop into cirrhosis or liver cancer. Curable in about 50% of cases by chemotherapy.
* Hep D: Caused by a small RNA virus that only propagates in the presence of hep B, greatly increasing the chance of cancer, cirrhosis and death. Hep B vaccine will prevent illness from D.
* Hep E: Transmitted by fecal-oral contamination in unsanitary conditions. Patients are generally very ill for the first few weeks of infection then the virus usually clears on it own. Vaccine is being tested.
Source: WSJ Reporting
---------------------------------------
"I was really, really sick for a while—I had to hide under the wedding gowns so I could nap," says Sidney Merry, 53, who works for a bridal retailer in Houston. Routine blood tests spotted her hep C, which she thinks she got from a blood transfusion in the 1970s, and later started treatment with Dr. Galati. Ms. Merry stuck with the program and is now free of the virus. She helps counsel other patients undergoing treatment.
Ms. Merry says two of her friends died of hep C they declined to treat, and her own mother died of liver cancer at age 53, from what Ms. Merry suspects may also have been hep C. "This touches many lives—but it's so unspoken about and misunderstood," she says.
Two new drugs on the horizon—boceprevir by Merck & Co. and telaprevir by Vertex Pharmaceuticals Inc.—are protease inhibitors similar to those in AIDS drugs. They could win approval by the Food and Drug Administration next year. Other companies are studying different approaches to fight hep C.
In July, the FDA approved a synthetic form of interferon, called Infergen, by Three Rivers Pharmaceuticals LLC, for use in daily injections for patients who don't respond to the first course of treatment.
In some cases, doctors are advising hep C patients to postpone treatment until the new drugs come on the market. But Dr. Galati, who has been the principal investigator for several industry-sponsored clinical trials, notes that the new drugs will be in addition to the current ones, so waiting for the new regimes won't allow patients to avoid the side effects.
Unborn babies can acquire hep C from infected mothers. Kathryn Maloney had complained of fatigue for years before she was diagnosed with hep C in 2005. "Turns out I had it my whole life and didn't know," says Ms. Maloney, 29, an accountant in Houston.
Since there was no obvious source of her infection, Dr. Galati suggested that her mother, Pamela Grant, be tested too. She tested positive as well, though she has no idea when or where she was exposed. She and her daughter underwent treatment together. They also took part in a clinical trial for one of the new medications and are now free of the virus.
Some patients opt to forgo treatment, since only about 20% progress to cirrhosis. But doctors can't tell in advance which cases will progress. Meanwhile, drinking alcohol, smoking cigarettes and carrying excess weight make cirrhosis more likely.
Some health experts are urging that the general public be screened for hep C; the blood test for antibodies costs only about $12. Short of that, liver specialists urge anyone who might have been exposed, no matter how or how long ago or how well they feel now, to tell their doctors and be tested.
Since hep C can carry a lingering stigma of past drug use, even though there are many other ways to contract it, Dr. Galati says some primary-care physicians routinely hand patients a list of risk factors and say, "If you fit into any of these categories, you should get tested. You don't need to tell me which one."
Evaluation of Versant Hepatitis C Virus Genotype Assay
Evaluation of Versant Hepatitis C Virus Genotype Assay (LiPA) 2.0 - pdf attached
Journal of Clinical Microbiology, June 2008, p. 1901-1906, Vol. 46, No. 6
doi:10.1128/JCM.02390-07
"The reliability of genotyping methods highly depends on the amount of information (i.e., the number of informative sites) that is utilized for the discrimination of genetic variants......Our results indicate that Versant HCV genotype assay (LiPA) 2.0 yielded an interpretable genotype result for 96.0% of the samples and that 99.4% of the interpretable results agreed with the reference method, rendering it an accurate and reliable assay suitable for large-scale genotyping. This new assay outperforms the previous version of the line probe assay, since Versant HCV genotype assay (LiPA) 1.0 has an overall accuracy of 74%, taking subtype i nformation into account (8, 23).....In conclusion, Versant HCV genotype assay (LiPA) 2.0 provides a rapid, sensitive, and accurate means of HCV genotyping and can be used as a routine tool to distinguish between the different HCV genotypes and subtypes. Considering the importance of genotype determination in understanding the epidemiology of the virus and in the management of hepatitis C treatment strategies, efficient genotyping tools are indispensable in clinical diagnostic settings."
Jannick Verbeeck,1 Mark J. Stanley,2 Jen Shieh,2 Linda Celis,3 Els Huyck,3 Elke Wollants,1 Judy Morimoto,2 Alice Farrior,2 Erwin Sablon,3 Margaret Jankowski-Hennig,4 Carl Schaper,4 Pamela Johnson,4 Marc Van Ranst,1* and Marianne Van Brussel3
Laboratory of Clinical Virology, Rega Institute for Medical Research, Leuven, Belgium,1 Department of Microbiology, Kaiser Permanente, TPMG Regional Laboratory, Berkeley, California,2 Innogenetics NV, Gent, Belgium,3 Siemens Healthcare Diagnostics, Berkeley, California4
ABSTRACT
Hepatitis C virus (HCV) genotyping is a tool used to optimize antiviral treatment regimens. The newly developed Versant HCV genotype assay (LiPA) 2.0 uses sequence information from both the 5' untranslated region and the core region, allowing distinction between HCV genotype 1 and subtypes c to l of genotype 6 and between subtypes a and b of genotype 1. HCV-positive samples were genotyped manually using the Versant HCV genotype assay (LiPA) 2.0 system according to the manufacturer's instructions. For the comparison study, Versant HCV genotype assay (LiPA) 1.0 was used. In this study, 99.7% of the samples could be amplified, the genotype of 96.0% of samples could be determined, and the agreement with the reference method was 99.4% when a genotype was determined. The reproducibility study showed no significant differences in performance across sites (P = 0.43) or across lots (P = 0.88). In the comparison stud y, 13 samples that were uninterpretable or incorrectly genotyped with Versant HCV genotype assay (LiPA) 1.0 were correctly genotyped by Versant HCV genotype assay (LiPA) 2.0. Versant HCV genotype assay (LiPA) 2.0 is a sensitive, accurate, and reliable assay for HCV genotyping. The inclusion of the core region probes in Versant HCV genotype assay (LiPA) 2.0 results in a genotyping success rate higher than that of the current Versant HCV genotype assay (LiPA) 1.0.
INTRODUCTION
Hepatitis C virus (HCV) is a leading cause of chronic liver disease and has already infected at least 170 million people worldwide. Each year, 3 to 4 million people are newly infected. HCV creates an extensive disease burden, since it accounts for 20 to 30% of cases of acute hepatitis, 70 to 80% of cases of chronic hepatitis, 40% of cases of end-stage cirrhosis, 50 to 76% of cases of hepatocellular carcinoma, and 30 to 40% of liver transplants (15, 33, 34).
HCV belongs to the family of the Flaviviridae and can be divided into different genotypes based on phylogenetic analysis of full-length or partial sequences of HCV strains. The most current consensus proposal distinguishes six genotypes based on phylogenetic cluster analysis of complete genomes. The genotype formerly designated as 10a has been reassigned as genotype 3, subtype k. Genotypes 7, 8, 9, and 11, belonging to clade 6, have been reassigned to genotype 6, subtypes c to l (25, 26, 27). These six HCV genotypes have different geographical distributions (21, 30, 32).
Treatment options for chronic HCV infections are poor. At the moment, the only accepted antiviral therapy with proven effectiveness is a combination therapy of (peg)interferon alpha and ribavirin. The overall success rate of this antiviral treatment ranges from 50% to 90% (11). According to a National Institutes of Health (NIH) 2002 panel, several factors are associated with successful treatment response, including lower baseline HCV RNA levels, lower fibrosis and inflammation scores upon liver biopsy, lower body weight, and lower body surface area, but the most important predicting factor is HCV genotype (24). Patients infected with HCV genotype 1 respond least to therapy, while patients infected with genotypes 2 and 3 show the best responses (14, 17, 22). For HCV genotypes 4, 5, and 6, treatment data are scarce, but it is recommended to treat these individuals using the same regimen as for patients infected with genotype 1 (7, 13, 18, 31). Nearly all patients experience side effects with the antiviral therapy. These side effects can be severe and contribute to discontinuation rates of 10 to 14% and dose reductions for 7 to 42% of patients, depending on the type and length of treatment (16). Therefore, it is important that clinicians have the appropriate information to make individual treatment choices in order to maximize the chance of successful treatment outcome for each individual patient, rendering HCV genotyping assays important and useful tools to optimize treatment type, duration, and dose.
In this paper, we evaluate Versant HCV genotype assay (LiPA) 2.0 (CE marked in Europe; for research use only; not for use in diagnostic procedures in the United States) (manufactured by Innogenetics, distributed by Siemens Healthcare Diagnostics), which uses sequence information from the core region in addition to sequence information from the 5' untranslated region (5'UTR), allowing an improved and more accurate distinction between HCV genotype 1 and subtypes c to l of genotype 6 and between subtypes a and b of genotype 1.
RESULTS
Clinical accuracy study.
Table 1 summarizes the results for the 326 specimens that were used for the reference method comparison. Upon initial testing, 93.3% (304/326) of the specimens gave interpretable genotype results, 2.1% (7/326) failed to amplify, and 4.6% (15/326) amplified but gave uninterpretable results. Of the 304 specimens that yielded a genotype result, 99.3% (302/304) gave results that agreed with the reference method. After specimens that yielded no genotype result were retested, 96.0% (313/326) of the specimens gave interpretable genotype results, 3.5% (12/326) amplified but remained uninterpretable, and 0.3% (1/326) failed to amplify. Of the 313 specimens that yielded a genotype result after repeat testing, 99.4% (311/313) gave results that agreed with the reference method. Table 2 shows that the specimens that did not amplify or give interpretable results were distributed across ge notypes. The two specimens that initially gave results that disagreed with those obtained by the reference method were retested, and both gave retest results that agreed with those obtained by the reference method.
In order to determine the core amplification efficiency, 156 genotype 1 and genotype 6 (c to l) samples were analyzed. Two samples showed negative AMPL CTRL 1 lines and were excluded from further analysis. Of the remaining 154 genotype 1 and genotype 6 (c to l) samples, 1 sample had a negative AMPL CTRL 2, r esulting in the amplification of 99.4% (153/154) samples.
The clinical subtype efficiency for HCV genotypes 1a and 1b was determined using 129 samples that were genotype 1a or 1b based on reference sequencing and genotype 1, 1a, or 1b based on LiPA genotyping; this determination was based on initial testing only, excluding repeat testing of initial amplification failures and uninterpretable results. Three out of 129 samples were indeterminate at the subtype level, resulting in a clinical HCV genotype 1 subtype efficiency of 97.7% after initial testing. Upon repeat testing, all samples gave a correct consensus subtype result. All of the 126 samples that were genotype 1a or 1b by LiPA were concordant with sequencing.
In order to check whether Versant HCV genotype assay (LiPA) 2.0 was able to determine the correct genotype for samples with viral loads at the upper limit of detection, 22 samples with viral loads ranging from 4.0 x 106 IU/ml to 8.7 x 106 IU/ml were selected, and the genotype success rate and the percentage of agreement with the reference method for these high-concentration specimens were estimated. For all these samples, Versant HCV genotype assay (LiPA) 2.0 produced the same genotype results as the genotype result determined by NS5b sequencing and phylogenetic analysis, resulting in both a genotype success rate and an agreement with the reference method of 100%.
Reproducibility study.
Table 3 summarizes the valid, indeterminate, correct, and incorrect genotype results for each reproducibility panel member. In total, 3.3% (16/486) of reactions gave indeterminate results (defined as specimens with either an amplification failure or an uninterpretable result) and 96.7% (LCL, 95.0%) yielded an interpretable genotype result. Of the 470 specimens with interpretable results, 100% (LCL, 99.4%) gave the correct genotype. The indeterminate results occurred at all sites, with all three reagent lots, and in multiple assay runs. There were no significant performance differences seen for the Versant HCV genotype assay (LiPA) 2.0 system across sites/operators (P = 0.43) or across reagent lots (P = 0.88). The genotype success rates at the individual sites were 98.1% for site 1, 97.6% for site 2, and 94.4% for site 3. The genotype success rates for the individual lots were 96.9% using lot 1, 97.5% using lot 2, and 95.7% using lot 3.
Comparison study.
Table 4 gives an overview of the results of the comparison study after original testing and after repeat testing. Of the 100 specimens tested, 13 specimens initially produced uninterpretable results by either Versant HCV genotype assay (LiPA) 1.0 or Versant HCV genotype assay (LiPA) 2.0 or both assays. The HCV RNA concentrations of these 13 samples ranged from 14,615 to 2,500,000 IU/ml. These specimens were retested using both ass ays. After repeat testing, three specimens remained uninterpretable by both versions of the assay, five remained uninterpretable by Versant HCV genotype assay (LiPA) 1.0, and one remained uninterpretable by Versant HCV genotype assay (LiPA) 2.0. For all six specimens that gave a genotype result by only one version of the assay, the observed genotype result agreed with that obtained by sequencing the NS5b region of the HCV genome. After repeat testing, 83 specimens were concordant by both assays at the genotype level. Of these, 16 specimens had concordant genotypes by both assays, but one of the assays failed to give a subtype, resulting in a total of 67 concordant specimens when the subtype level is taken into account. Results from eight specimens were discordant between the two assays, and results from nine specimens were uninterpretable by at least one of the assays. The total number of interpretable specimens by both assays was 91, of which 83 had concordant results at the genotype level only (91.2%; LCL, 84.7%). Table 5 shows the number o f genotype and subtype results produced by both assays for the 100 specimens tested after repeat testing.
The eight samples that showed discordant results were sequenced in the NS5b region of the HCV genome (two samples were HCV genotype 6 subtypes c to l, and six samples were HCV genotype 1a). Results indicated that Versant HCV genotype assay (LiPA) 2.0 gave the correct HCV genotype and subtype, as determined by NS5b sequencing. In contrast, Versant HCV genotype assay (LiPA) 1.0 had misclassified all eight samples as HC V genotype 1b. Of the 96 specimens that were interpretable with Versant HCV genotype assay (LiPA) 2.0, 83 showed concordant results with Versant HCV genotype assay (LiPA) 1.0, while 13 showed improved results over Versant HCV genotype assay (LiPA) 1.0, which leads to 100% concordant or improved results (LCL, 96.9%).
DISCUSSION
Phylogenetic analysis of a coding region, or even more, the complete genome, is considered the gold standard for identifying different HCV genotypes (6). However, since this method is expensive and time-consuming, it is impractical for large-scale genotyping projects (8). For this reason, commercial genotyping kits were developed for routine determination of HCV genotypes. Most commercially available HCV genotyping assays, including Versant HCV genotype assay (LiPA) 1.0, use the 5'UTR, since this region is highly conserved and therefore well suited for the development of detection methods. The reliability of genotyping methods highly depends on the amount of information (i.e., the number of informative sites) that is utilized for the discrimination of genetic variants. The 5'UTR is sufficiently variable for discrimination of HCV genotypes 1 to 5 and most subtypes of HCV genotype 6 (12, 28, 29, 32). However, it does not allow discrimination of HCV genotype 6 subtypes c to l from HCV genotype 1 and has only a limited subtyping accuracy (5, 29). To overcome the limitations of the 5'UTR, a new assay which uses additional sequence information from the core region of the HCV genome, Versant HCV genotype assay (LiPA) 2.0, has recently been developed (20). In this study, we evaluated the new assay and compared it with the previous version of the assay.
Our results indicate that Versant HCV genotype assay (LiPA) 2.0 yielded an interpretable genotype result for 96.0% of the samples and that 99.4% of the interpretable results agreed with the reference method, rendering it an accurate and reliable assay suitable for large-scale genotyping. This new assay outperforms the previous version of the line probe assay, since Versant HCV genotype assay (LiPA) 1.0 has an overall accuracy of 74%, taking subtype information into account (8, 23).
In the comparison study, eight specimens showed discordant results when tested with both assays. The NS5b sequencing results for these samples showed that Versant HCV genotype assay (LiPA) 2.0 gave the correct HCV genotype and subtype and thereby showed an improvement in identifying HCV-positive samples which are subtypes c to l of genotype 6 and in identifying the correct subtype of genotype 1. This improvement can be attributed to the additional information available from the core region of the HCV genome, which can better distinguish between genotype 1 and subtypes c to l of genotype 6 and between subtype a and b of genotype 1. This core information is not available in Versant HCV genotype assay (LiPA) 1.0, and this can lead to misinterpretation. For example, in a study by Chinchai et al., this assay could not discriminate HCV genotype 6a variants from HCV genotype 1b, and two samples found to be genotype 1 by the assay contained genotype 3 core sequences (5). Chen and Weck showed that Versant HCV genotype assay (LiPA) 1.0 cannot accurately distinguish HCV genotypes 1a and 1b, since in most cases, the 5'UTR is not heterogeneous enough for use in determining the HCV subtype (4). Several other studies report on moderate distinction at the subtype level (1, 2, 9, 12, 19). This is not surprising, since the 5'UTR is the most highly conserved region of the HCV genome, and only one or two nucleotide changes distinguish unique subtypes. Assigning correct genotypes and subtypes to HCV specimens is important for several research purposes, including epidemiological, phylogenetic, and natural history studies. Some studies even report that there is a slight difference in treatment outcomes between HCV genotype 1a- and HCV genotype 1b-infected patients, showing that correct subtype assignment is indispensable (3, 10, 30).
In conclusion, Versant HCV genotype assay (LiPA) 2.0 provides a rapid, sensitive, and accurate means of HCV genotyping and can be used as a routine tool to distinguish between the different HCV genotypes and subtypes. Considering the importance of genotype determination in understanding the epidemiology of the virus and in the management of hepatitis C treatment strategies, efficient genotyping tools are indispensable in clinical diagnostic settings.
Journal of Clinical Microbiology, June 2008, p. 1901-1906, Vol. 46, No. 6
doi:10.1128/JCM.02390-07
"The reliability of genotyping methods highly depends on the amount of information (i.e., the number of informative sites) that is utilized for the discrimination of genetic variants......Our results indicate that Versant HCV genotype assay (LiPA) 2.0 yielded an interpretable genotype result for 96.0% of the samples and that 99.4% of the interpretable results agreed with the reference method, rendering it an accurate and reliable assay suitable for large-scale genotyping. This new assay outperforms the previous version of the line probe assay, since Versant HCV genotype assay (LiPA) 1.0 has an overall accuracy of 74%, taking subtype i nformation into account (8, 23).....In conclusion, Versant HCV genotype assay (LiPA) 2.0 provides a rapid, sensitive, and accurate means of HCV genotyping and can be used as a routine tool to distinguish between the different HCV genotypes and subtypes. Considering the importance of genotype determination in understanding the epidemiology of the virus and in the management of hepatitis C treatment strategies, efficient genotyping tools are indispensable in clinical diagnostic settings."
Jannick Verbeeck,1 Mark J. Stanley,2 Jen Shieh,2 Linda Celis,3 Els Huyck,3 Elke Wollants,1 Judy Morimoto,2 Alice Farrior,2 Erwin Sablon,3 Margaret Jankowski-Hennig,4 Carl Schaper,4 Pamela Johnson,4 Marc Van Ranst,1* and Marianne Van Brussel3
Laboratory of Clinical Virology, Rega Institute for Medical Research, Leuven, Belgium,1 Department of Microbiology, Kaiser Permanente, TPMG Regional Laboratory, Berkeley, California,2 Innogenetics NV, Gent, Belgium,3 Siemens Healthcare Diagnostics, Berkeley, California4
ABSTRACT
Hepatitis C virus (HCV) genotyping is a tool used to optimize antiviral treatment regimens. The newly developed Versant HCV genotype assay (LiPA) 2.0 uses sequence information from both the 5' untranslated region and the core region, allowing distinction between HCV genotype 1 and subtypes c to l of genotype 6 and between subtypes a and b of genotype 1. HCV-positive samples were genotyped manually using the Versant HCV genotype assay (LiPA) 2.0 system according to the manufacturer's instructions. For the comparison study, Versant HCV genotype assay (LiPA) 1.0 was used. In this study, 99.7% of the samples could be amplified, the genotype of 96.0% of samples could be determined, and the agreement with the reference method was 99.4% when a genotype was determined. The reproducibility study showed no significant differences in performance across sites (P = 0.43) or across lots (P = 0.88). In the comparison stud y, 13 samples that were uninterpretable or incorrectly genotyped with Versant HCV genotype assay (LiPA) 1.0 were correctly genotyped by Versant HCV genotype assay (LiPA) 2.0. Versant HCV genotype assay (LiPA) 2.0 is a sensitive, accurate, and reliable assay for HCV genotyping. The inclusion of the core region probes in Versant HCV genotype assay (LiPA) 2.0 results in a genotyping success rate higher than that of the current Versant HCV genotype assay (LiPA) 1.0.
INTRODUCTION
Hepatitis C virus (HCV) is a leading cause of chronic liver disease and has already infected at least 170 million people worldwide. Each year, 3 to 4 million people are newly infected. HCV creates an extensive disease burden, since it accounts for 20 to 30% of cases of acute hepatitis, 70 to 80% of cases of chronic hepatitis, 40% of cases of end-stage cirrhosis, 50 to 76% of cases of hepatocellular carcinoma, and 30 to 40% of liver transplants (15, 33, 34).
HCV belongs to the family of the Flaviviridae and can be divided into different genotypes based on phylogenetic analysis of full-length or partial sequences of HCV strains. The most current consensus proposal distinguishes six genotypes based on phylogenetic cluster analysis of complete genomes. The genotype formerly designated as 10a has been reassigned as genotype 3, subtype k. Genotypes 7, 8, 9, and 11, belonging to clade 6, have been reassigned to genotype 6, subtypes c to l (25, 26, 27). These six HCV genotypes have different geographical distributions (21, 30, 32).
Treatment options for chronic HCV infections are poor. At the moment, the only accepted antiviral therapy with proven effectiveness is a combination therapy of (peg)interferon alpha and ribavirin. The overall success rate of this antiviral treatment ranges from 50% to 90% (11). According to a National Institutes of Health (NIH) 2002 panel, several factors are associated with successful treatment response, including lower baseline HCV RNA levels, lower fibrosis and inflammation scores upon liver biopsy, lower body weight, and lower body surface area, but the most important predicting factor is HCV genotype (24). Patients infected with HCV genotype 1 respond least to therapy, while patients infected with genotypes 2 and 3 show the best responses (14, 17, 22). For HCV genotypes 4, 5, and 6, treatment data are scarce, but it is recommended to treat these individuals using the same regimen as for patients infected with genotype 1 (7, 13, 18, 31). Nearly all patients experience side effects with the antiviral therapy. These side effects can be severe and contribute to discontinuation rates of 10 to 14% and dose reductions for 7 to 42% of patients, depending on the type and length of treatment (16). Therefore, it is important that clinicians have the appropriate information to make individual treatment choices in order to maximize the chance of successful treatment outcome for each individual patient, rendering HCV genotyping assays important and useful tools to optimize treatment type, duration, and dose.
In this paper, we evaluate Versant HCV genotype assay (LiPA) 2.0 (CE marked in Europe; for research use only; not for use in diagnostic procedures in the United States) (manufactured by Innogenetics, distributed by Siemens Healthcare Diagnostics), which uses sequence information from the core region in addition to sequence information from the 5' untranslated region (5'UTR), allowing an improved and more accurate distinction between HCV genotype 1 and subtypes c to l of genotype 6 and between subtypes a and b of genotype 1.
RESULTS
Clinical accuracy study.
Table 1 summarizes the results for the 326 specimens that were used for the reference method comparison. Upon initial testing, 93.3% (304/326) of the specimens gave interpretable genotype results, 2.1% (7/326) failed to amplify, and 4.6% (15/326) amplified but gave uninterpretable results. Of the 304 specimens that yielded a genotype result, 99.3% (302/304) gave results that agreed with the reference method. After specimens that yielded no genotype result were retested, 96.0% (313/326) of the specimens gave interpretable genotype results, 3.5% (12/326) amplified but remained uninterpretable, and 0.3% (1/326) failed to amplify. Of the 313 specimens that yielded a genotype result after repeat testing, 99.4% (311/313) gave results that agreed with the reference method. Table 2 shows that the specimens that did not amplify or give interpretable results were distributed across ge notypes. The two specimens that initially gave results that disagreed with those obtained by the reference method were retested, and both gave retest results that agreed with those obtained by the reference method.
In order to determine the core amplification efficiency, 156 genotype 1 and genotype 6 (c to l) samples were analyzed. Two samples showed negative AMPL CTRL 1 lines and were excluded from further analysis. Of the remaining 154 genotype 1 and genotype 6 (c to l) samples, 1 sample had a negative AMPL CTRL 2, r esulting in the amplification of 99.4% (153/154) samples.
The clinical subtype efficiency for HCV genotypes 1a and 1b was determined using 129 samples that were genotype 1a or 1b based on reference sequencing and genotype 1, 1a, or 1b based on LiPA genotyping; this determination was based on initial testing only, excluding repeat testing of initial amplification failures and uninterpretable results. Three out of 129 samples were indeterminate at the subtype level, resulting in a clinical HCV genotype 1 subtype efficiency of 97.7% after initial testing. Upon repeat testing, all samples gave a correct consensus subtype result. All of the 126 samples that were genotype 1a or 1b by LiPA were concordant with sequencing.
In order to check whether Versant HCV genotype assay (LiPA) 2.0 was able to determine the correct genotype for samples with viral loads at the upper limit of detection, 22 samples with viral loads ranging from 4.0 x 106 IU/ml to 8.7 x 106 IU/ml were selected, and the genotype success rate and the percentage of agreement with the reference method for these high-concentration specimens were estimated. For all these samples, Versant HCV genotype assay (LiPA) 2.0 produced the same genotype results as the genotype result determined by NS5b sequencing and phylogenetic analysis, resulting in both a genotype success rate and an agreement with the reference method of 100%.
Reproducibility study.
Table 3 summarizes the valid, indeterminate, correct, and incorrect genotype results for each reproducibility panel member. In total, 3.3% (16/486) of reactions gave indeterminate results (defined as specimens with either an amplification failure or an uninterpretable result) and 96.7% (LCL, 95.0%) yielded an interpretable genotype result. Of the 470 specimens with interpretable results, 100% (LCL, 99.4%) gave the correct genotype. The indeterminate results occurred at all sites, with all three reagent lots, and in multiple assay runs. There were no significant performance differences seen for the Versant HCV genotype assay (LiPA) 2.0 system across sites/operators (P = 0.43) or across reagent lots (P = 0.88). The genotype success rates at the individual sites were 98.1% for site 1, 97.6% for site 2, and 94.4% for site 3. The genotype success rates for the individual lots were 96.9% using lot 1, 97.5% using lot 2, and 95.7% using lot 3.
Comparison study.
Table 4 gives an overview of the results of the comparison study after original testing and after repeat testing. Of the 100 specimens tested, 13 specimens initially produced uninterpretable results by either Versant HCV genotype assay (LiPA) 1.0 or Versant HCV genotype assay (LiPA) 2.0 or both assays. The HCV RNA concentrations of these 13 samples ranged from 14,615 to 2,500,000 IU/ml. These specimens were retested using both ass ays. After repeat testing, three specimens remained uninterpretable by both versions of the assay, five remained uninterpretable by Versant HCV genotype assay (LiPA) 1.0, and one remained uninterpretable by Versant HCV genotype assay (LiPA) 2.0. For all six specimens that gave a genotype result by only one version of the assay, the observed genotype result agreed with that obtained by sequencing the NS5b region of the HCV genome. After repeat testing, 83 specimens were concordant by both assays at the genotype level. Of these, 16 specimens had concordant genotypes by both assays, but one of the assays failed to give a subtype, resulting in a total of 67 concordant specimens when the subtype level is taken into account. Results from eight specimens were discordant between the two assays, and results from nine specimens were uninterpretable by at least one of the assays. The total number of interpretable specimens by both assays was 91, of which 83 had concordant results at the genotype level only (91.2%; LCL, 84.7%). Table 5 shows the number o f genotype and subtype results produced by both assays for the 100 specimens tested after repeat testing.
The eight samples that showed discordant results were sequenced in the NS5b region of the HCV genome (two samples were HCV genotype 6 subtypes c to l, and six samples were HCV genotype 1a). Results indicated that Versant HCV genotype assay (LiPA) 2.0 gave the correct HCV genotype and subtype, as determined by NS5b sequencing. In contrast, Versant HCV genotype assay (LiPA) 1.0 had misclassified all eight samples as HC V genotype 1b. Of the 96 specimens that were interpretable with Versant HCV genotype assay (LiPA) 2.0, 83 showed concordant results with Versant HCV genotype assay (LiPA) 1.0, while 13 showed improved results over Versant HCV genotype assay (LiPA) 1.0, which leads to 100% concordant or improved results (LCL, 96.9%).
DISCUSSION
Phylogenetic analysis of a coding region, or even more, the complete genome, is considered the gold standard for identifying different HCV genotypes (6). However, since this method is expensive and time-consuming, it is impractical for large-scale genotyping projects (8). For this reason, commercial genotyping kits were developed for routine determination of HCV genotypes. Most commercially available HCV genotyping assays, including Versant HCV genotype assay (LiPA) 1.0, use the 5'UTR, since this region is highly conserved and therefore well suited for the development of detection methods. The reliability of genotyping methods highly depends on the amount of information (i.e., the number of informative sites) that is utilized for the discrimination of genetic variants. The 5'UTR is sufficiently variable for discrimination of HCV genotypes 1 to 5 and most subtypes of HCV genotype 6 (12, 28, 29, 32). However, it does not allow discrimination of HCV genotype 6 subtypes c to l from HCV genotype 1 and has only a limited subtyping accuracy (5, 29). To overcome the limitations of the 5'UTR, a new assay which uses additional sequence information from the core region of the HCV genome, Versant HCV genotype assay (LiPA) 2.0, has recently been developed (20). In this study, we evaluated the new assay and compared it with the previous version of the assay.
Our results indicate that Versant HCV genotype assay (LiPA) 2.0 yielded an interpretable genotype result for 96.0% of the samples and that 99.4% of the interpretable results agreed with the reference method, rendering it an accurate and reliable assay suitable for large-scale genotyping. This new assay outperforms the previous version of the line probe assay, since Versant HCV genotype assay (LiPA) 1.0 has an overall accuracy of 74%, taking subtype information into account (8, 23).
In the comparison study, eight specimens showed discordant results when tested with both assays. The NS5b sequencing results for these samples showed that Versant HCV genotype assay (LiPA) 2.0 gave the correct HCV genotype and subtype and thereby showed an improvement in identifying HCV-positive samples which are subtypes c to l of genotype 6 and in identifying the correct subtype of genotype 1. This improvement can be attributed to the additional information available from the core region of the HCV genome, which can better distinguish between genotype 1 and subtypes c to l of genotype 6 and between subtype a and b of genotype 1. This core information is not available in Versant HCV genotype assay (LiPA) 1.0, and this can lead to misinterpretation. For example, in a study by Chinchai et al., this assay could not discriminate HCV genotype 6a variants from HCV genotype 1b, and two samples found to be genotype 1 by the assay contained genotype 3 core sequences (5). Chen and Weck showed that Versant HCV genotype assay (LiPA) 1.0 cannot accurately distinguish HCV genotypes 1a and 1b, since in most cases, the 5'UTR is not heterogeneous enough for use in determining the HCV subtype (4). Several other studies report on moderate distinction at the subtype level (1, 2, 9, 12, 19). This is not surprising, since the 5'UTR is the most highly conserved region of the HCV genome, and only one or two nucleotide changes distinguish unique subtypes. Assigning correct genotypes and subtypes to HCV specimens is important for several research purposes, including epidemiological, phylogenetic, and natural history studies. Some studies even report that there is a slight difference in treatment outcomes between HCV genotype 1a- and HCV genotype 1b-infected patients, showing that correct subtype assignment is indispensable (3, 10, 30).
In conclusion, Versant HCV genotype assay (LiPA) 2.0 provides a rapid, sensitive, and accurate means of HCV genotyping and can be used as a routine tool to distinguish between the different HCV genotypes and subtypes. Considering the importance of genotype determination in understanding the epidemiology of the virus and in the management of hepatitis C treatment strategies, efficient genotyping tools are indispensable in clinical diagnostic settings.
Hepatitis C Virus (HCV) Genotype 1 Subtype Identification in New HCV Drug Development and Future Clinical Practice
Hepatitis C Virus (HCV) Genotype 1 Subtype Identification in New HCV Drug Development and Future Clinical Practice - pdf attached
PLoS ONE 4(12): e8209. doi:10.1371/journal.pone.0008209
Published December 8, 2009
"INNO-LiPA HCV 2.0 currently is the best available commercial assay for HCV genotype 1 subtype identification and should be used in clinical trials and practice.....
Trugene HCV Genotyping Kit and INNO-LiPA HCV 1.0, failed to correctly identify HCV subtype 1a in 22.8% and 29.5% of cases, and HCV subtype 1b in 9.5% and 8.7% of cases, respectively....
The second-generation line probe assay is currently the best commercial assay for determination of HCV genotype 1 subtypes 1a and 1b. It can therefore be used locally in clinical trials to identify the HCV subtype and stratify the patients at inclusion, as well as to interpret efficacy and resistance data. When reporting final data, direct sequence analysis of the NS5B region and/or another coding region (for instance the region encoding the antiviral drug target HCV protein) should always be performed as it may identify mistyping or mis-subtyping with commercial assays, especially in the case of rare subtypes."
Stéphane Chevaliez1,2, Magali Bouvier-Alias1,2, Rozenn Brillet2, Jean-Michel Pawlotsky1,2*
1 French National Reference Center for Viral Hepatitis B, C and delta, Department of Virology, Hôpital Henri Mondor, Université Paris 12, Créteil, France, 2 INSERM U955, Créteil, France
Methods based on the sole analysis of the 5′NCR, namely Trugene HCV Genotyping Kit and INNO-LiPA HCV 1.0, failed to correctly identify HCV subtype 1a in 22.8% and 29.5% of cases, and HCV subtype 1b in 9.5% and 8.7% of cases, respectively (Table 1)......
The results clearly show that, although they are by far the most widely used techniques in new HCV drug development trials, genotyping techniques based on the sole analysis of the 5′NCR should be avoided, as they mistype approximately 25% and 10% of HCV subtype 1a and 1b strains, respectively......
INNO-LiPA HCV 2.0 displays the same 5′NCR oligonucleotide probes as INNO-LiPA HCV 1.0, plus core-encoded oligonucleotide probes aimed at better discriminating between HCV subtypes 1a and 1b. With INNO-LiPA HCV 2.0, subtype identification was corrected in 64 of the 70 subtypes 1a that were incorrectly typed with INNO-LiPA HCV 1.0. Five samples could not be PCR-amplified in the core-coding region and the result was not interpretable with INNO-LiPA HCV 2.0 in the remaining case (Table 1). INNO-LiPA HCV 2.0 also corrected subtype identification in 13 of 23 subtypes 1b that were incorrectly typed with INNO-LiPA HCV 1.0. Eight samples could not be PCR-amplified in the core-coding region and the result was not interpretable with INNO-LiPA HCV 2.0 in the remaining two cases (Table 1). Overall, the second-generation line probe assay correctly classified 97.5% of subtype 1a and 96.2% of subtype 1b strains. When only samples that could be PCR-amplified with the assay procedure were taken into account, correct subtype determination was achieved in 99.6% and 99.2% of cases, respectively (Table 1)
The real-time PCR-based assay targeting both the 5′NCR and the NS5B region, Abbott RealTime HCV Genotype II assay, correctly identified 93.2% of subtype 1a and 88.9% of subtype 1b strains. Only 2 HCV subtype 1b samples could not be PCR-amplified with this method (Table 1)......
Novel assays have been recently developed that aim at better discriminating among the different HCV genotype 1 subtypes and between genotypes 1 and 6. Abbott RealTime HCV Genotype II assay is a real-time PCR method using several sets of genotype- and subtype-specific primers and probes located in both the 5′NCR and the NS5B-coding region. As shown in Table 1, adding a second target region for analysis led to substantially improving HCV genotype 1 subtype identification compared to methods targeting the sole 5′NCR. However, in contrast with a previous report [33], we found that this assay failed to correctly identify HCV genotype 1 subtype in approximately 10% of cases.
Table 1. Ability of the different molecular methods tested in this study to correctly identify HCV subtypes 1a and 1b in a series of 500 patients infected by one or the other of these subtypes.
Screen shot 2010-09-18 at 7.38.55 AM.png
Abstract
Background
With the development of new specific inhibitors of hepatitis C virus (HCV) enzymes and functions that may yield different antiviral responses and resistance profiles according to the HCV subtype, correct HCV genotype 1 subtype identification is mandatory in clinical trials for stratification and interpretation purposes and will likely become necessary in future clinical practice. The goal of this study was to identify the appropriate molecular tool(s) for accurate HCV genotype 1 subtype determination.
Methodology/Principal Findings
A large cohort of 500 treatment-naïve patients eligible for HCV drug trials and infected with either subtype 1a or 1b was studied. Methods based on the sole analysis of the 5′ non-coding region (5′NCR) by sequence analysis or reverse hybridization failed to correctly identify HCV subtype 1a in 22.8%–29.5% of cases, and HCV subtype 1b in 9.5%–8.7% of cases. Natural polymorphisms at positions 107, 204 and/or 243 were responsible for mis-subtyping with these methods. A real-time PCR method using genotype- and subtype-specific primers and probes located in both the 5′NCR and the NS5B-coding region failed to correctly identify HCV genotype 1 subtype in approximately 10% of cases. The second-generation line probe assay, a reverse hybridization assay that uses probes targeting both the 5′NCR and core-coding region, correctly identified HCV subtypes 1a and 1b in more than 99% of cases.
Conclusions/Significance
In the context of new HCV drug development, HCV genotyping methods based on the exclusive analysis of the 5′NCR should be avoided. The second-generation line probe assay is currently the best commercial assay for determination of HCV genotype 1 subtypes 1a and 1b in clinical trials and practice.
Funding: The Trugene HCV 5′NC Genotyping kits and the INNO-LiPA HCV kits were kindly provided by Siemens Medical Solutions Diagnostics. The Abbott RealTime HCV Genotype II kits were kindly provided by Abbott Molecular. This work is part of the activity of the VIRGIL European Network of Excellence on Antiviral Drug Resistance supported by a grant (LSHM-CT-2004-503359) from the Priority 1 “Life Sciences, Genomics and Biotechnology for Health” program in the 6th Framework Program of the European Union. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Introduction
Over 170 million individuals are infected with hepatitis C virus (HCV) worldwide. Phylogenetic analyses have shown that HCV strains can be classified into at least 6 major genotypes (numbered 1 to 6), and a large number of subtypes within each genotype [1]. Genotype 1 is by far the most frequent genotype in chronically infected patients worldwide, with subtypes 1a and 1b representing the vast majority of circulating strains [2], [3], [4].
Current treatment of chronic hepatitis C is based on the combination of pegylated interferon (IFN)-α and ribavirin [5]. This treatment fails to eradicate infection in 50%–60% of patients infected with HCV genotype 1 and approximately 20% of those infected with HCV genotypes 2 and 3 [6], [7], [8]. Thus the need for more efficacious therapies is urgent, especially for patients infected with HCV genotype 1. A number of novel antiviral molecules currently are in preclinical or clinical development [9]. The most advanced ones are specific inhibitors of viral enzymes and functions involved in the HCV life cycle. Molecules that have reached clinical development include inhibitors of the nonstructural (NS) 3/4A serine protease and inhibitors of HCV replication that belong to different categories: nucleoside/nucleotide analogue and non-nucleoside inhibitors of the HCV RNA-dependent RNA polymerase (RdRp), NS5A inhibitors and cyclophilin inhibitors [9]. These agents have shown potent antiviral efficacy when used alone, and encouraging results have been recently published showing that HCV clearance can be achieved in approximately 70% of cases when a potent NS3/4A inhibitor is used in combination with pegylated IFN-α and ribavirin [10], [11], [12].
HCV genotype 1 is generally considered as a homogeneous group. There are however biological differences between the different subtypes of HCV genotype 1, which are related to differences in their nucleotide and amino acid sequences. Importantly, differences between subtype 1a and 1b (by far the most frequently encountered genotype 1 subtypes in clinical practice) include different efficacies of antiviral drugs and different resistance profiles to such drugs. Indeed, several HCV inhibitors appear to have selective activity against different HCV genotype 1 subtypes, both in vitro and in vivo. Differences have been observed in vitro with NS3/4A protease inhibitors, non-nucleoside inhibitors of HCV RdRp and NS5A inhibitors [13], [14], [15], [16], [17]. For instance, BILB 1941, a non-nucleoside inhibitor of HCV RdRp, has been shown to have better antiviral efficacy in patients infected with HCV subtype 1b than in those infected with HCV subtype 1a, a finding reflecting in vitro experiments [13].
A major issue that limits the efficacy of direct acting antiviral therapies for HCV is the selection by these drugs of resistant variants upon administration [18]. Recent studies with NS3/4A protease inhibitors have shown that the genetic barrier and resistance profiles substantially differ between the different genotype 1 subtypes. For instance, the Arg to Lys substitution at position 155 of the NS3 protease (R155K) is usually selected in subtype 1a replicons treated with telaprevir, but not in subtype 1b replicons [19]. The reason is that only one nucleotide substitution is needed relative to the subtype 1a sequence to generate this variant, whereas two substitutions are needed relative to the 1b sequence (codon usage bias). Overall, natural polymorphisms at positions R155 and V36 are frequent in subtype 1a, but rare in subtype 1b where substitutions at position A156 are preferentially selected in vitro [19]. This is reflected in vivo by the different resistance profiles in patients infected by HCV subtypes 1a and 1b. In the former, the V36 and R155 substitutions represent the backbone of resistance, whereas in the latter resistance is less frequent as it is preferentially associated with substitutions at position A156 that are associated with a decreased fitness of the variants [19], [20], [21]. Similarly, important differences in the resistance profiles have been described in vitro with HCV-796, a non-nucleoside inhibitor of HCV RdRp. The C316Y amino acid substitution has been reported to be selected in both subtype 1a and 1b replicon cells. However, in genotype 1a replicons, the C316Y substitution has low replication capacity that must be compensated for by additional “compensatory” substitutions, including L392F or M414T, resulting in an increase in replication levels of at least 10-fold [19]. A higher genetic barrier to resistance to HCV-796 and related compounds is therefore expected in patients infected with HCV subtype 1a than 1b. In vivo, HCV-796 monotherapy was however shown to select subtype 1a variants with a single C316Y substitution, whereas the C316Y substitution was associated with a number of additional substitutions in subtype 1b patients [22].
As a result of these findings, correct identification of HCV subtypes 1a and 1b is crucial in clinical trials assessing new HCV drugs in order to correctly stratify and interpret efficacy and resistance data. It may also become important in future clinical practice, as tailoring treatment schedules with HCV inhibitors to HCV genotype 1 subtype might become necessary. A variety of molecular methods can be used to identify the HCV genotype and subtype both in clinical trials and practice. Commercial assays have been developed, most of them targeting the 5′ noncoding region (5′NCR) of the HCV genome, although this region is the most conserved one. These methods have been shown to differentiate well the different HCV genotypes (1 to 6), except genotype 1 from genotype 6, a rare HCV genotype in the Western world [23], [24]. The goal of our study was to assess the ability of molecular methods targeting the 5′NCR to correctly identify the HCV genotype 1 subtype in patients eligible for clinical trials, and to identify the best method for this purpose.
Results
Hepatitis C Virus Genotype and Subtype Determination by Phylogenetic Analysis of a Portion of the NS5B Gene
Direct sequence analysis of a sufficiently long portion of the NS5B gene followed by phylogenetic analysis is the reference method for identification of HCV genotype and subtype [1], [25]. It was used to identify the HCV genotype and subtype in 516 treatment-naïve patients included in a multicenter clinical trial assessing different schedules of pegylated IFN-α2a and ribavirin [26]. All of these patients were thought to be infected with HCV genotype 1 at inclusion based on local assessment. In fact, 6 patients were infected with genotype 6, including 2 with subtype 6e, one with subtype 6o, one with subtype 6p, one with subtype 6q and one with subtype 6r. These 6 samples were not considered for further analysis in the present study. The remaining 510 patients were confirmed to be infected with HCV genotype 1: 237 of them (46.5%) were infected with HCV subtype 1a and 263 (51.6%) with subtype 1b (Figure 1). As shown in Figure 1, HCV subtype 1a strains segregated into two distinct clades, that were termed 1a clade I (n = 83, 35.0%) and 1a clade II (n = 154, 65.0%). Eight patients (1.6%) were infected with another HCV genotype 1 subtype, including 4 patients with subtype 1d, 2 with subtype 1e, one with subtype 1i, and one with subtype 1l. The remaining 2 patients (0.3%) were infected with genotype 1 but the subtype could not be determined. The ability of the different molecular methods to correctly identify HCV subtypes 1a and 1b was then tested on the 237 and 263 samples containing HCV subtypes 1a and 1b, respectively.
INNO-LiPA HCV 2.0 displays the same 5′NCR oligonucleotide probes as INNO-LiPA HCV 1.0, plus core-encoded oligonucleotide probes aimed at better discriminating between HCV subtypes 1a and 1b. With INNO-LiPA HCV 2.0, subtype identification was corrected in 64 of the 70 subtypes 1a that were incorrectly typed with INNO-LiPA HCV 1.0. Five samples could not be PCR-amplified in the core-coding region and the result was not interpretable with INNO-LiPA HCV 2.0 in the remaining case (Table 1). INNO-LiPA HCV 2.0 also corrected subtype identification in 13 of 23 subtypes 1b that were incorrectly typed with INNO-LiPA HCV 1.0. Eight samples could not be PCR-amplified in the core-coding region and the result was not interpretable with INNO-LiPA HCV 2.0 in the remaining two cases (Table 1). Overall, the second-generation line probe assay correctly classified 97.5% of subtype 1a and 96.2% of subtype 1b strains. When only samples that could be PCR-amplified with the assay procedure were taken into account, correct subtype determination was achieved in 99.6% and 99.2% of cases, respectively (Table 1).
The real-time PCR-based assay targeting both the 5′NCR and the NS5B region, Abbott RealTime HCV Genotype II assay, correctly identified 93.2% of subtype 1a and 88.9% of subtype 1b strains. Only 2 HCV subtype 1b samples could not be PCR-amplified with this method (Table 1).
5′NCR Sequence Analysis in Misclassified Subtype 1a Strains
Among the HCV subtype 1a strains, 47 were misclassified as subtype 1b by Trugene HCV Genotyping Kit and/or INNO-LiPA HCV 1.0, including 33 that were misclassified by both assays, 7 that were misclassified by Trugene HCV Genotyping Kit only, and 7 that were misclassified by INNO-LiPA HCV 1.0 only (Table 2). Figure 2 shows an alignment of their 5′NCR sequences relative to the consensus sequences of the correctly classified strains (including subtype 1a clade I, subtype 1a clade II and subtype 1b). As shown in Figure 2, misclassification of subtype 1a strains into subtype 1b in one or both assays was related to the presence of natural polymorphisms at nucleotide positions 204 and 243, both of which are located within the sequence of an INNO-LiPA HCV 1.0 probe. At position 243, A is the most frequent nucleotide in HCV subtype 1a, in both subtype 1a clade I and clade II. Substitution into a G, the most frequent nucleotide at position 243 in subtype 1b, was found in all cases that were misclassified as subtype 1b by Trugene HCV Genotyping Kit and/or INNO-LiPA HCV 1.0 (Figure 2). At position 204, A is the most frequent nucleotide for subtype 1a clade I, whereas C is the most frequent nucleotide for subtype 1a clade II, and C or T are the most frequent nucleotides for subtype 1b. In spite of the presence of a G at position 243, the presence of an A at position 204 allowed correct identification of subtype 1a with Trugene HCV Genotyping Kit but not with INNO-LiPA HCV 1.0 (Figure 2). The usual presence of a C at position 204 in subtype 1a clade II explains why misclassifications were far more frequent with this clade than with subtype 1a clade I.
Among the 12 subtype 1a strains that were classified as genotype 1, indeterminate subtype with Trugene HCV Genotyping Kit, one had a G and 5 had mixed A and G populations at position 243. Two additional patients with an A at position 243 had a C at position 248. In the remaining 4 cases, no explanation was found in the 5′NCR sequence for the failure to identify the HCV subtype (data not shown). Among the 25 subtype 1a strains that were classified as genotype 1, indeterminate subtype with INNO-LiPA HCV 1.0 (including 6 with the same profile in Trugene HCV Genotyping Kit), 4 had a G and 4 had mixed A and G populations at position 243. Three additional patients with an A at position 243 had a C at position 248 (C only in two of them, a mixture of C and T in one). In the 14 remaining cases, no explanation was found in the 5′NCR sequence for the failure to identify the HCV subtype (data not shown).
5′NCR Sequence Analysis in Misclassified Subtype 1b Strains
Among HCV subtype 1b strains, 8 were misclassified as subtype 1a by Trugene HCV Genotyping Kit and/or INNO-LiPA HCV 1.0, including 3 that were misclassified by both assays, 4 that were misclassified by Trugene HCV Genotyping Kit only, and 1 that was misclassified by INNO-LiPA HCV 1.0 only (Table 2). Figure 3 shows an alignment of their 5′NCR sequences relative to the consensus sequences of the correctly classified subtype 1a and subtype 1b strains. As shown in Figure 3, and as for misclassified subtype 1a strains discussed above, misclassification of subtype 1b strains into subtype 1a was related to the presence of natural polymorphisms at positions 204 and 243. At position 243, G is the most frequent nucleotide in HCV subtype 1b. Substitution into an A, the most frequent nucleotide at position 243 in subtype 1a, was found in all cases that were misclassified as subtype 1a by both Trugene HCV Genotyping Kit and INNO-LiPA HCV 1.0 and by INNO-LiPA HCV 1.0 only, but not in those that were misclassified by Trugene HCV Genotyping Kit only (Figure 3). In the latter, it is the presence of an A at position 204 instead of a C or a T that was responsible for misclassification in all but one case (Figure 3).
Among the 11 subtype 1b strains that were classified as genotype 1, indeterminate subtype with Trugene HCV Genotyping Kit, one had an A at position 243. In the remaining cases, no explanation was found in the 5′NCR sequence for the failure to identify the HCV subtype (data not shown). Among the 15 subtype 1b strains that were classified as genotype 1, indeterminate subtype with INNO-LiPA HCV 1.0 (none of which were classified as indeterminate in Trugene HCV Genotyping Kit), one had an A and one harbored mixed A and G populations at position 243. Both of them had a C at position 248 (C only in one of them and a mixture of C and T in the other one). In the remaining 13 cases, no explanation was found in the 5′NCR sequence for the failure to identify the HCV subtype (data not shown).
Incorrect Subtyping with Abbott RealTime HCV Genotype II Assay, that Targets Both the 5′NCR and NS5B Region
Among the HCV subtype 1a strains, 16 were incorrectly classified by Abbott RealTime HCV Genotype II assay (Table 1): 2 were misclassified as subtype 1b, 12 were classified as genotype 1, indeterminate subtype, one was identified as a mixed 1a/1b infection, and one gave an indeterminate result. In one case, PCR amplification failed, and in one case, not enough serum volume was available for testing.
Among the HCV subtype 1b strains, 27 were incorrectly classified by Abbott RealTime HCV Genotype II assay (Table 1): 3 were misclassified as subtype 1a, 18 were classified as genotype 1, indeterminate subtype, 5 were identified as a mixed 1a/1b infection, and one gave an indeterminate result. In 2 cases, PCR amplification failed, and in one case, not enough serum volume was available for testing.
PLoS ONE 4(12): e8209. doi:10.1371/journal.pone.0008209
Published December 8, 2009
"INNO-LiPA HCV 2.0 currently is the best available commercial assay for HCV genotype 1 subtype identification and should be used in clinical trials and practice.....
Trugene HCV Genotyping Kit and INNO-LiPA HCV 1.0, failed to correctly identify HCV subtype 1a in 22.8% and 29.5% of cases, and HCV subtype 1b in 9.5% and 8.7% of cases, respectively....
The second-generation line probe assay is currently the best commercial assay for determination of HCV genotype 1 subtypes 1a and 1b. It can therefore be used locally in clinical trials to identify the HCV subtype and stratify the patients at inclusion, as well as to interpret efficacy and resistance data. When reporting final data, direct sequence analysis of the NS5B region and/or another coding region (for instance the region encoding the antiviral drug target HCV protein) should always be performed as it may identify mistyping or mis-subtyping with commercial assays, especially in the case of rare subtypes."
Stéphane Chevaliez1,2, Magali Bouvier-Alias1,2, Rozenn Brillet2, Jean-Michel Pawlotsky1,2*
1 French National Reference Center for Viral Hepatitis B, C and delta, Department of Virology, Hôpital Henri Mondor, Université Paris 12, Créteil, France, 2 INSERM U955, Créteil, France
Methods based on the sole analysis of the 5′NCR, namely Trugene HCV Genotyping Kit and INNO-LiPA HCV 1.0, failed to correctly identify HCV subtype 1a in 22.8% and 29.5% of cases, and HCV subtype 1b in 9.5% and 8.7% of cases, respectively (Table 1)......
The results clearly show that, although they are by far the most widely used techniques in new HCV drug development trials, genotyping techniques based on the sole analysis of the 5′NCR should be avoided, as they mistype approximately 25% and 10% of HCV subtype 1a and 1b strains, respectively......
INNO-LiPA HCV 2.0 displays the same 5′NCR oligonucleotide probes as INNO-LiPA HCV 1.0, plus core-encoded oligonucleotide probes aimed at better discriminating between HCV subtypes 1a and 1b. With INNO-LiPA HCV 2.0, subtype identification was corrected in 64 of the 70 subtypes 1a that were incorrectly typed with INNO-LiPA HCV 1.0. Five samples could not be PCR-amplified in the core-coding region and the result was not interpretable with INNO-LiPA HCV 2.0 in the remaining case (Table 1). INNO-LiPA HCV 2.0 also corrected subtype identification in 13 of 23 subtypes 1b that were incorrectly typed with INNO-LiPA HCV 1.0. Eight samples could not be PCR-amplified in the core-coding region and the result was not interpretable with INNO-LiPA HCV 2.0 in the remaining two cases (Table 1). Overall, the second-generation line probe assay correctly classified 97.5% of subtype 1a and 96.2% of subtype 1b strains. When only samples that could be PCR-amplified with the assay procedure were taken into account, correct subtype determination was achieved in 99.6% and 99.2% of cases, respectively (Table 1)
The real-time PCR-based assay targeting both the 5′NCR and the NS5B region, Abbott RealTime HCV Genotype II assay, correctly identified 93.2% of subtype 1a and 88.9% of subtype 1b strains. Only 2 HCV subtype 1b samples could not be PCR-amplified with this method (Table 1)......
Novel assays have been recently developed that aim at better discriminating among the different HCV genotype 1 subtypes and between genotypes 1 and 6. Abbott RealTime HCV Genotype II assay is a real-time PCR method using several sets of genotype- and subtype-specific primers and probes located in both the 5′NCR and the NS5B-coding region. As shown in Table 1, adding a second target region for analysis led to substantially improving HCV genotype 1 subtype identification compared to methods targeting the sole 5′NCR. However, in contrast with a previous report [33], we found that this assay failed to correctly identify HCV genotype 1 subtype in approximately 10% of cases.
Table 1. Ability of the different molecular methods tested in this study to correctly identify HCV subtypes 1a and 1b in a series of 500 patients infected by one or the other of these subtypes.
Screen shot 2010-09-18 at 7.38.55 AM.png
Abstract
Background
With the development of new specific inhibitors of hepatitis C virus (HCV) enzymes and functions that may yield different antiviral responses and resistance profiles according to the HCV subtype, correct HCV genotype 1 subtype identification is mandatory in clinical trials for stratification and interpretation purposes and will likely become necessary in future clinical practice. The goal of this study was to identify the appropriate molecular tool(s) for accurate HCV genotype 1 subtype determination.
Methodology/Principal Findings
A large cohort of 500 treatment-naïve patients eligible for HCV drug trials and infected with either subtype 1a or 1b was studied. Methods based on the sole analysis of the 5′ non-coding region (5′NCR) by sequence analysis or reverse hybridization failed to correctly identify HCV subtype 1a in 22.8%–29.5% of cases, and HCV subtype 1b in 9.5%–8.7% of cases. Natural polymorphisms at positions 107, 204 and/or 243 were responsible for mis-subtyping with these methods. A real-time PCR method using genotype- and subtype-specific primers and probes located in both the 5′NCR and the NS5B-coding region failed to correctly identify HCV genotype 1 subtype in approximately 10% of cases. The second-generation line probe assay, a reverse hybridization assay that uses probes targeting both the 5′NCR and core-coding region, correctly identified HCV subtypes 1a and 1b in more than 99% of cases.
Conclusions/Significance
In the context of new HCV drug development, HCV genotyping methods based on the exclusive analysis of the 5′NCR should be avoided. The second-generation line probe assay is currently the best commercial assay for determination of HCV genotype 1 subtypes 1a and 1b in clinical trials and practice.
Funding: The Trugene HCV 5′NC Genotyping kits and the INNO-LiPA HCV kits were kindly provided by Siemens Medical Solutions Diagnostics. The Abbott RealTime HCV Genotype II kits were kindly provided by Abbott Molecular. This work is part of the activity of the VIRGIL European Network of Excellence on Antiviral Drug Resistance supported by a grant (LSHM-CT-2004-503359) from the Priority 1 “Life Sciences, Genomics and Biotechnology for Health” program in the 6th Framework Program of the European Union. The funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.
Introduction
Over 170 million individuals are infected with hepatitis C virus (HCV) worldwide. Phylogenetic analyses have shown that HCV strains can be classified into at least 6 major genotypes (numbered 1 to 6), and a large number of subtypes within each genotype [1]. Genotype 1 is by far the most frequent genotype in chronically infected patients worldwide, with subtypes 1a and 1b representing the vast majority of circulating strains [2], [3], [4].
Current treatment of chronic hepatitis C is based on the combination of pegylated interferon (IFN)-α and ribavirin [5]. This treatment fails to eradicate infection in 50%–60% of patients infected with HCV genotype 1 and approximately 20% of those infected with HCV genotypes 2 and 3 [6], [7], [8]. Thus the need for more efficacious therapies is urgent, especially for patients infected with HCV genotype 1. A number of novel antiviral molecules currently are in preclinical or clinical development [9]. The most advanced ones are specific inhibitors of viral enzymes and functions involved in the HCV life cycle. Molecules that have reached clinical development include inhibitors of the nonstructural (NS) 3/4A serine protease and inhibitors of HCV replication that belong to different categories: nucleoside/nucleotide analogue and non-nucleoside inhibitors of the HCV RNA-dependent RNA polymerase (RdRp), NS5A inhibitors and cyclophilin inhibitors [9]. These agents have shown potent antiviral efficacy when used alone, and encouraging results have been recently published showing that HCV clearance can be achieved in approximately 70% of cases when a potent NS3/4A inhibitor is used in combination with pegylated IFN-α and ribavirin [10], [11], [12].
HCV genotype 1 is generally considered as a homogeneous group. There are however biological differences between the different subtypes of HCV genotype 1, which are related to differences in their nucleotide and amino acid sequences. Importantly, differences between subtype 1a and 1b (by far the most frequently encountered genotype 1 subtypes in clinical practice) include different efficacies of antiviral drugs and different resistance profiles to such drugs. Indeed, several HCV inhibitors appear to have selective activity against different HCV genotype 1 subtypes, both in vitro and in vivo. Differences have been observed in vitro with NS3/4A protease inhibitors, non-nucleoside inhibitors of HCV RdRp and NS5A inhibitors [13], [14], [15], [16], [17]. For instance, BILB 1941, a non-nucleoside inhibitor of HCV RdRp, has been shown to have better antiviral efficacy in patients infected with HCV subtype 1b than in those infected with HCV subtype 1a, a finding reflecting in vitro experiments [13].
A major issue that limits the efficacy of direct acting antiviral therapies for HCV is the selection by these drugs of resistant variants upon administration [18]. Recent studies with NS3/4A protease inhibitors have shown that the genetic barrier and resistance profiles substantially differ between the different genotype 1 subtypes. For instance, the Arg to Lys substitution at position 155 of the NS3 protease (R155K) is usually selected in subtype 1a replicons treated with telaprevir, but not in subtype 1b replicons [19]. The reason is that only one nucleotide substitution is needed relative to the subtype 1a sequence to generate this variant, whereas two substitutions are needed relative to the 1b sequence (codon usage bias). Overall, natural polymorphisms at positions R155 and V36 are frequent in subtype 1a, but rare in subtype 1b where substitutions at position A156 are preferentially selected in vitro [19]. This is reflected in vivo by the different resistance profiles in patients infected by HCV subtypes 1a and 1b. In the former, the V36 and R155 substitutions represent the backbone of resistance, whereas in the latter resistance is less frequent as it is preferentially associated with substitutions at position A156 that are associated with a decreased fitness of the variants [19], [20], [21]. Similarly, important differences in the resistance profiles have been described in vitro with HCV-796, a non-nucleoside inhibitor of HCV RdRp. The C316Y amino acid substitution has been reported to be selected in both subtype 1a and 1b replicon cells. However, in genotype 1a replicons, the C316Y substitution has low replication capacity that must be compensated for by additional “compensatory” substitutions, including L392F or M414T, resulting in an increase in replication levels of at least 10-fold [19]. A higher genetic barrier to resistance to HCV-796 and related compounds is therefore expected in patients infected with HCV subtype 1a than 1b. In vivo, HCV-796 monotherapy was however shown to select subtype 1a variants with a single C316Y substitution, whereas the C316Y substitution was associated with a number of additional substitutions in subtype 1b patients [22].
As a result of these findings, correct identification of HCV subtypes 1a and 1b is crucial in clinical trials assessing new HCV drugs in order to correctly stratify and interpret efficacy and resistance data. It may also become important in future clinical practice, as tailoring treatment schedules with HCV inhibitors to HCV genotype 1 subtype might become necessary. A variety of molecular methods can be used to identify the HCV genotype and subtype both in clinical trials and practice. Commercial assays have been developed, most of them targeting the 5′ noncoding region (5′NCR) of the HCV genome, although this region is the most conserved one. These methods have been shown to differentiate well the different HCV genotypes (1 to 6), except genotype 1 from genotype 6, a rare HCV genotype in the Western world [23], [24]. The goal of our study was to assess the ability of molecular methods targeting the 5′NCR to correctly identify the HCV genotype 1 subtype in patients eligible for clinical trials, and to identify the best method for this purpose.
Results
Hepatitis C Virus Genotype and Subtype Determination by Phylogenetic Analysis of a Portion of the NS5B Gene
Direct sequence analysis of a sufficiently long portion of the NS5B gene followed by phylogenetic analysis is the reference method for identification of HCV genotype and subtype [1], [25]. It was used to identify the HCV genotype and subtype in 516 treatment-naïve patients included in a multicenter clinical trial assessing different schedules of pegylated IFN-α2a and ribavirin [26]. All of these patients were thought to be infected with HCV genotype 1 at inclusion based on local assessment. In fact, 6 patients were infected with genotype 6, including 2 with subtype 6e, one with subtype 6o, one with subtype 6p, one with subtype 6q and one with subtype 6r. These 6 samples were not considered for further analysis in the present study. The remaining 510 patients were confirmed to be infected with HCV genotype 1: 237 of them (46.5%) were infected with HCV subtype 1a and 263 (51.6%) with subtype 1b (Figure 1). As shown in Figure 1, HCV subtype 1a strains segregated into two distinct clades, that were termed 1a clade I (n = 83, 35.0%) and 1a clade II (n = 154, 65.0%). Eight patients (1.6%) were infected with another HCV genotype 1 subtype, including 4 patients with subtype 1d, 2 with subtype 1e, one with subtype 1i, and one with subtype 1l. The remaining 2 patients (0.3%) were infected with genotype 1 but the subtype could not be determined. The ability of the different molecular methods to correctly identify HCV subtypes 1a and 1b was then tested on the 237 and 263 samples containing HCV subtypes 1a and 1b, respectively.
INNO-LiPA HCV 2.0 displays the same 5′NCR oligonucleotide probes as INNO-LiPA HCV 1.0, plus core-encoded oligonucleotide probes aimed at better discriminating between HCV subtypes 1a and 1b. With INNO-LiPA HCV 2.0, subtype identification was corrected in 64 of the 70 subtypes 1a that were incorrectly typed with INNO-LiPA HCV 1.0. Five samples could not be PCR-amplified in the core-coding region and the result was not interpretable with INNO-LiPA HCV 2.0 in the remaining case (Table 1). INNO-LiPA HCV 2.0 also corrected subtype identification in 13 of 23 subtypes 1b that were incorrectly typed with INNO-LiPA HCV 1.0. Eight samples could not be PCR-amplified in the core-coding region and the result was not interpretable with INNO-LiPA HCV 2.0 in the remaining two cases (Table 1). Overall, the second-generation line probe assay correctly classified 97.5% of subtype 1a and 96.2% of subtype 1b strains. When only samples that could be PCR-amplified with the assay procedure were taken into account, correct subtype determination was achieved in 99.6% and 99.2% of cases, respectively (Table 1).
The real-time PCR-based assay targeting both the 5′NCR and the NS5B region, Abbott RealTime HCV Genotype II assay, correctly identified 93.2% of subtype 1a and 88.9% of subtype 1b strains. Only 2 HCV subtype 1b samples could not be PCR-amplified with this method (Table 1).
5′NCR Sequence Analysis in Misclassified Subtype 1a Strains
Among the HCV subtype 1a strains, 47 were misclassified as subtype 1b by Trugene HCV Genotyping Kit and/or INNO-LiPA HCV 1.0, including 33 that were misclassified by both assays, 7 that were misclassified by Trugene HCV Genotyping Kit only, and 7 that were misclassified by INNO-LiPA HCV 1.0 only (Table 2). Figure 2 shows an alignment of their 5′NCR sequences relative to the consensus sequences of the correctly classified strains (including subtype 1a clade I, subtype 1a clade II and subtype 1b). As shown in Figure 2, misclassification of subtype 1a strains into subtype 1b in one or both assays was related to the presence of natural polymorphisms at nucleotide positions 204 and 243, both of which are located within the sequence of an INNO-LiPA HCV 1.0 probe. At position 243, A is the most frequent nucleotide in HCV subtype 1a, in both subtype 1a clade I and clade II. Substitution into a G, the most frequent nucleotide at position 243 in subtype 1b, was found in all cases that were misclassified as subtype 1b by Trugene HCV Genotyping Kit and/or INNO-LiPA HCV 1.0 (Figure 2). At position 204, A is the most frequent nucleotide for subtype 1a clade I, whereas C is the most frequent nucleotide for subtype 1a clade II, and C or T are the most frequent nucleotides for subtype 1b. In spite of the presence of a G at position 243, the presence of an A at position 204 allowed correct identification of subtype 1a with Trugene HCV Genotyping Kit but not with INNO-LiPA HCV 1.0 (Figure 2). The usual presence of a C at position 204 in subtype 1a clade II explains why misclassifications were far more frequent with this clade than with subtype 1a clade I.
Among the 12 subtype 1a strains that were classified as genotype 1, indeterminate subtype with Trugene HCV Genotyping Kit, one had a G and 5 had mixed A and G populations at position 243. Two additional patients with an A at position 243 had a C at position 248. In the remaining 4 cases, no explanation was found in the 5′NCR sequence for the failure to identify the HCV subtype (data not shown). Among the 25 subtype 1a strains that were classified as genotype 1, indeterminate subtype with INNO-LiPA HCV 1.0 (including 6 with the same profile in Trugene HCV Genotyping Kit), 4 had a G and 4 had mixed A and G populations at position 243. Three additional patients with an A at position 243 had a C at position 248 (C only in two of them, a mixture of C and T in one). In the 14 remaining cases, no explanation was found in the 5′NCR sequence for the failure to identify the HCV subtype (data not shown).
5′NCR Sequence Analysis in Misclassified Subtype 1b Strains
Among HCV subtype 1b strains, 8 were misclassified as subtype 1a by Trugene HCV Genotyping Kit and/or INNO-LiPA HCV 1.0, including 3 that were misclassified by both assays, 4 that were misclassified by Trugene HCV Genotyping Kit only, and 1 that was misclassified by INNO-LiPA HCV 1.0 only (Table 2). Figure 3 shows an alignment of their 5′NCR sequences relative to the consensus sequences of the correctly classified subtype 1a and subtype 1b strains. As shown in Figure 3, and as for misclassified subtype 1a strains discussed above, misclassification of subtype 1b strains into subtype 1a was related to the presence of natural polymorphisms at positions 204 and 243. At position 243, G is the most frequent nucleotide in HCV subtype 1b. Substitution into an A, the most frequent nucleotide at position 243 in subtype 1a, was found in all cases that were misclassified as subtype 1a by both Trugene HCV Genotyping Kit and INNO-LiPA HCV 1.0 and by INNO-LiPA HCV 1.0 only, but not in those that were misclassified by Trugene HCV Genotyping Kit only (Figure 3). In the latter, it is the presence of an A at position 204 instead of a C or a T that was responsible for misclassification in all but one case (Figure 3).
Among the 11 subtype 1b strains that were classified as genotype 1, indeterminate subtype with Trugene HCV Genotyping Kit, one had an A at position 243. In the remaining cases, no explanation was found in the 5′NCR sequence for the failure to identify the HCV subtype (data not shown). Among the 15 subtype 1b strains that were classified as genotype 1, indeterminate subtype with INNO-LiPA HCV 1.0 (none of which were classified as indeterminate in Trugene HCV Genotyping Kit), one had an A and one harbored mixed A and G populations at position 243. Both of them had a C at position 248 (C only in one of them and a mixture of C and T in the other one). In the remaining 13 cases, no explanation was found in the 5′NCR sequence for the failure to identify the HCV subtype (data not shown).
Incorrect Subtyping with Abbott RealTime HCV Genotype II Assay, that Targets Both the 5′NCR and NS5B Region
Among the HCV subtype 1a strains, 16 were incorrectly classified by Abbott RealTime HCV Genotype II assay (Table 1): 2 were misclassified as subtype 1b, 12 were classified as genotype 1, indeterminate subtype, one was identified as a mixed 1a/1b infection, and one gave an indeterminate result. In one case, PCR amplification failed, and in one case, not enough serum volume was available for testing.
Among the HCV subtype 1b strains, 27 were incorrectly classified by Abbott RealTime HCV Genotype II assay (Table 1): 3 were misclassified as subtype 1a, 18 were classified as genotype 1, indeterminate subtype, 5 were identified as a mixed 1a/1b infection, and one gave an indeterminate result. In 2 cases, PCR amplification failed, and in one case, not enough serum volume was available for testing.
Pegasys Patient Assistance Program
Pegasys Patient Assistance Program
has generous provisions for patients who want to start HCV therapy with Pegasys and are uninsured. Since Roche & Genentech merged the Genentech Access Solutions P rogram took over this program starting Sept 1 2010 and as I say it is a generous transparent program.
http://www.pegasysaccesssolutions.com
866 422-2377
has generous provisions for patients who want to start HCV therapy with Pegasys and are uninsured. Since Roche & Genentech merged the Genentech Access Solutions P rogram took over this program starting Sept 1 2010 and as I say it is a generous transparent program.
http://www.pegasysaccesssolutions.com
866 422-2377
Healthcare-Associated Infections (HAIs)
I've reached out to you in the past about Kimberly-Clark's efforts to lead the fight against Healthcare-Associated Infections (HAIs). I wanted to follow up with some very exciting news. Kimberly-Clark has launched a new online program - the HAI WATCHDOG* Community - where healthcare providers can discuss best practices for defeating HAIs. The goal is to help eliminate these often preventable infections through discussion and education.
The HAI WATCHDOG* Community allows members to start discussions, post photos, videos and even enter the 2010 HAI WATCHDOG* Awards. Entering the awards program not only allows healthcare providers to share and learn from each other, but also gives contest participants the opportunity to be rewarded for their efforts with an educational grant.
I would love for you to join the community and share this news with the readers of HCV Awareness. I've created a microsite which explains everything:
http://haiwatchnews.com
If you are able to post about this, I'd love to get the link to your post. Please let me know if you have any questions or need more information.
Thank you,
Barbara
--
Barbara Dunn
barbara@haiwatchnews.com
haiwatch.com
haiwatchdog.com
The HAI WATCHDOG* Community allows members to start discussions, post photos, videos and even enter the 2010 HAI WATCHDOG* Awards. Entering the awards program not only allows healthcare providers to share and learn from each other, but also gives contest participants the opportunity to be rewarded for their efforts with an educational grant.
I would love for you to join the community and share this news with the readers of HCV Awareness. I've created a microsite which explains everything:
http://haiwatchnews.com
If you are able to post about this, I'd love to get the link to your post. Please let me know if you have any questions or need more information.
Thank you,
Barbara
--
Barbara Dunn
barbara@haiwatchnews.com
haiwatch.com
haiwatchdog.com
9-9-10 NYC Hep B & C Advocacy Committee Meeting Highlights
9-9-10 NYC Hep B & C Advocacy Committee Meeting Highlights
Tuesday, September 14, 2010 5:40 PM
From:
"Nirah Johnson"
View contact details
To:
undisclosed-recipients
Message contains attachments
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NYC Hepatitis B & C Advocacy Meeting Highlights
September 9th 2010 (10 AM-12) - New York Organ Donor Network: 460 West 34th Street , 15th Floor, New York , NY 10001
NYC Hepatitis B & C Advocacy Committee Website
Next Meeting: October 21st!
In attendance: see below
Meeting Highlights
* Hepatitis B & C Advocacy Committee Strategic Plan Development Discussion
· Wish list
o A Community Health Center (FQHC) Comprehensive Hepatitis B & C Program in each borough
o NYC DOHMH to provide:
§ HBV testing at public health clinics (STD or Immunization)
§ Full panel of HBV Tests
§ HCV PCR (Confirmatory) Testing
o Hepatitis B & C Health Educator Certification
o Hepatitis B & C Testing Protocol Package
§ Pre & Post Test Counseling Certification
§ Referral process protocol
o Methadone Clinics, Detox Centers : Enhanced Hepatitis B & C, testing, treatment services and supportive services (case management)
o Corrections: Rikers - Enhanced Hepatitis B & C, testing, treatment services and supportive services (case management/discharge planning)
o Faith Based Organizations: Integration of Hepatitis B & C into Health Education
o 1 minute Hepatitis B & C Public Service Announcement for the General Public. Translated into major languages.
o Hepatitis B Patient Advocate cohort who are willing to speak publicly about their experience
o HBV Anti-stigma campaign
* Planning for October 19th Viral Hepatitis Awareness City Council Legislative Breakfast
· Advocacy committee members and team leaders will call their Council person and invite to event (not yet – official invites have not gone out)
Hepatitis B & C Community Partners,
Please register a representative from your organization for this exciting awareness event!
NYC Hepatitis B & C Awareness Breakfast
Sponsored by
NYC City Council Members
Maria del Carmen Arroyo, Margaret Chin & Peter Koo
Organized by
NYC Hepatitis B Coalition & NYC Hepatitis C Task Force
NYC Department of Health & Mental Hygiene - Office of Viral Hepatitis Coordination
Tuesday October 19th
9 – 10:30 AM
Albella - 10 Reade Street, NY 10007 - www.albellanyc.com - map
Breakfast buffet will be served
Program:
* Introduction by NYC Council
* Information about Hepatitis B & C and how these life threatening chronic diseases impact NYC
* Testimonials by NYC residents affected by Hepatitis B & C
* Networking with NYC residents, community organizations representing the Hepatitis B & C populations and NYC Council Members
Please join us in representing the NYC Viral Hepatitis Community by designating one representative from your organization to attend the event! RSVP to: njohnso2@health.nyc.gov as soon as possible.
Updates
* Victory! NY Congressman Charles Rangel signed on to Viral Hepatitis and Liver Cancer Control & Prevention Act (H.R. 3974)! Congratulations NYC Hepatitis B & C Advocacy Committee for your hard work!
* Kerry Introduces Bill to Fight Viral Hepatitis – Senate
o Disrupting a deadly disease - Hepatitis defense can save thousands of lives a year. By Sen. John Kerry and Rep. Michael M. Honda. The Washington Times
In Attendance
* Benjamin Vines, Health Educator – AIDS Service Center of NY
* Daniel Raymond, National Policy Director – Harm Reduction Coalition
* Dara Hunt, Advocate
* Eric Rude, Director Office of Viral Hepatitis Coordination DOHMH
* Fred Wright – VOCAL
* Jacqueline Aguilar Taylor – Bilingual Health Educator, Coney Island
* Joseph Prioleau, Health Educator – AIDS Service Center of NY
* Justina Wu, NYU B FREE CEED
* Kevin Lo - Charles B Wang Community Health Center
* Michael Carden, Project Director – Center for the Study of Hepatitis C
* Nirah Johnson – DOHMH
* Ronni Marks, HCV Support Group Leader & Advocate
**********************************************************************
The New York City Department of Health & Mental Hygiene is now offering information important for the health of all New Yorkers. To sign up for these new and valuable updates, log-on to our website at http://www.nyc.gov/health/email and select the NYC DOHMH updates you'd like to receive.
IMPORTANT NOTICE: This email is meant only for the use of the intended recipient. It may contain confidential information that is legally privileged or otherwise protected by law. If you have received this communication in error, please notify me immediately by replying to this message and please delete it from your computer. Thank you for your cooperation.
Tuesday, September 14, 2010 5:40 PM
From:
"Nirah Johnson"
View contact details
To:
undisclosed-recipients
Message contains attachments
2 Files (8KB) | Download All
* image002.jpgimage002.jpg
* image001.jpgimage001.jpg
NYC Hepatitis B & C Advocacy Meeting Highlights
September 9th 2010 (10 AM-12) - New York Organ Donor Network: 460 West 34th Street , 15th Floor, New York , NY 10001
NYC Hepatitis B & C Advocacy Committee Website
Next Meeting: October 21st!
In attendance: see below
Meeting Highlights
* Hepatitis B & C Advocacy Committee Strategic Plan Development Discussion
· Wish list
o A Community Health Center (FQHC) Comprehensive Hepatitis B & C Program in each borough
o NYC DOHMH to provide:
§ HBV testing at public health clinics (STD or Immunization)
§ Full panel of HBV Tests
§ HCV PCR (Confirmatory) Testing
o Hepatitis B & C Health Educator Certification
o Hepatitis B & C Testing Protocol Package
§ Pre & Post Test Counseling Certification
§ Referral process protocol
o Methadone Clinics, Detox Centers : Enhanced Hepatitis B & C, testing, treatment services and supportive services (case management)
o Corrections: Rikers - Enhanced Hepatitis B & C, testing, treatment services and supportive services (case management/discharge planning)
o Faith Based Organizations: Integration of Hepatitis B & C into Health Education
o 1 minute Hepatitis B & C Public Service Announcement for the General Public. Translated into major languages.
o Hepatitis B Patient Advocate cohort who are willing to speak publicly about their experience
o HBV Anti-stigma campaign
* Planning for October 19th Viral Hepatitis Awareness City Council Legislative Breakfast
· Advocacy committee members and team leaders will call their Council person and invite to event (not yet – official invites have not gone out)
Hepatitis B & C Community Partners,
Please register a representative from your organization for this exciting awareness event!
NYC Hepatitis B & C Awareness Breakfast
Sponsored by
NYC City Council Members
Maria del Carmen Arroyo, Margaret Chin & Peter Koo
Organized by
NYC Hepatitis B Coalition & NYC Hepatitis C Task Force
NYC Department of Health & Mental Hygiene - Office of Viral Hepatitis Coordination
Tuesday October 19th
9 – 10:30 AM
Albella - 10 Reade Street, NY 10007 - www.albellanyc.com - map
Breakfast buffet will be served
Program:
* Introduction by NYC Council
* Information about Hepatitis B & C and how these life threatening chronic diseases impact NYC
* Testimonials by NYC residents affected by Hepatitis B & C
* Networking with NYC residents, community organizations representing the Hepatitis B & C populations and NYC Council Members
Please join us in representing the NYC Viral Hepatitis Community by designating one representative from your organization to attend the event! RSVP to: njohnso2@health.nyc.gov as soon as possible.
Updates
* Victory! NY Congressman Charles Rangel signed on to Viral Hepatitis and Liver Cancer Control & Prevention Act (H.R. 3974)! Congratulations NYC Hepatitis B & C Advocacy Committee for your hard work!
* Kerry Introduces Bill to Fight Viral Hepatitis – Senate
o Disrupting a deadly disease - Hepatitis defense can save thousands of lives a year. By Sen. John Kerry and Rep. Michael M. Honda. The Washington Times
In Attendance
* Benjamin Vines, Health Educator – AIDS Service Center of NY
* Daniel Raymond, National Policy Director – Harm Reduction Coalition
* Dara Hunt, Advocate
* Eric Rude, Director Office of Viral Hepatitis Coordination DOHMH
* Fred Wright – VOCAL
* Jacqueline Aguilar Taylor – Bilingual Health Educator, Coney Island
* Joseph Prioleau, Health Educator – AIDS Service Center of NY
* Justina Wu, NYU B FREE CEED
* Kevin Lo - Charles B Wang Community Health Center
* Michael Carden, Project Director – Center for the Study of Hepatitis C
* Nirah Johnson – DOHMH
* Ronni Marks, HCV Support Group Leader & Advocate
**********************************************************************
The New York City Department of Health & Mental Hygiene is now offering information important for the health of all New Yorkers. To sign up for these new and valuable updates, log-on to our website at http://www.nyc.gov/health/email and select the NYC DOHMH updates you'd like to receive.
IMPORTANT NOTICE: This email is meant only for the use of the intended recipient. It may contain confidential information that is legally privileged or otherwise protected by law. If you have received this communication in error, please notify me immediately by replying to this message and please delete it from your computer. Thank you for your cooperation.
NYC Hepatitis B & C Awareness Breakfast
Hepatitis B & C Community Partners,
Please register a representative from your organization for this exciting awareness event!
NYC Hepatitis B & C Awareness Breakfast
Sponsored by
NYC City Council Members
Maria del Carmen Arroyo, Margaret Chin & Peter Koo
Organized by
NYC Hepatitis B Coalition & NYC Hepatitis C Task Force
NYC Department of Health & Mental Hygiene - Office of Viral Hepatitis Coordination
Tuesday October 19th
9 – 10:30 AM
Albella - 10 Reade Street, NY 10007 - www.albellanyc.com - map
Breakfast buffet will be served
Program:
* Introduction by NYC Council
* Information about Hepatitis B & C and how these life threatening chronic diseases impact NYC
* Testimonials by NYC residents affected by Hepatitis B & C
* Networking with NYC residents, community organizations representing the Hepatitis B & C populations and NYC Council Members
Please join us in representing the NYC Viral Hepatitis Community by designating one representative from your organization to attend the event! RSVP to: njohnso2@health.nyc.gov as soon as possible.
**********************************************************************
The New York City Department of Health & Mental Hygiene is now offering information important for the health of all New Yorkers. To sign up for these new and valuable updates, log-on to our website at http://www.nyc.gov/health/email and select the NYC DOHMH updates you'd like to receive.
IMPORTANT NOTICE: This email is meant only for the use of the intended recipient. It may contain confidential information tha
Please register a representative from your organization for this exciting awareness event!
NYC Hepatitis B & C Awareness Breakfast
Sponsored by
NYC City Council Members
Maria del Carmen Arroyo, Margaret Chin & Peter Koo
Organized by
NYC Hepatitis B Coalition & NYC Hepatitis C Task Force
NYC Department of Health & Mental Hygiene - Office of Viral Hepatitis Coordination
Tuesday October 19th
9 – 10:30 AM
Albella - 10 Reade Street, NY 10007 - www.albellanyc.com - map
Breakfast buffet will be served
Program:
* Introduction by NYC Council
* Information about Hepatitis B & C and how these life threatening chronic diseases impact NYC
* Testimonials by NYC residents affected by Hepatitis B & C
* Networking with NYC residents, community organizations representing the Hepatitis B & C populations and NYC Council Members
Please join us in representing the NYC Viral Hepatitis Community by designating one representative from your organization to attend the event! RSVP to: njohnso2@health.nyc.gov as soon as possible.
**********************************************************************
The New York City Department of Health & Mental Hygiene is now offering information important for the health of all New Yorkers. To sign up for these new and valuable updates, log-on to our website at http://www.nyc.gov/health/email and select the NYC DOHMH updates you'd like to receive.
IMPORTANT NOTICE: This email is meant only for the use of the intended recipient. It may contain confidential information tha
Guidance for Industry Chronic Hepatitis C Virus Infection: Developing Direct- Acting Antiviral Agents for Treatment DRAFT GUIDANCE
Guidance for Industry
Chronic Hepatitis C Virus
Infection: Developing Direct-
Acting Antiviral Agents for
Treatment
DRAFT GUIDANCE
This guidance document is being distributed for comment purposes only.
Comments and suggestions regarding this draft document should be submitted within 60 days of publication in the Federal Register of the notice announcing the availability of the draft guidance. Submit comments to the Division of Dockets Management (HFA-305), Food and Drug Administration, 5630 Fishers Lane, rm. 1061, Rockville, MD 20852. All comments should be identified with the docket number listed in the notice of availability that publishes in the Federal Register.
For questions regarding this draft document contact Jeffrey Murray at (301) 796-1500.
U.S. Department of Health and Human Services
Food and Drug Administration
Center for Drug Evaluation and Research (CDER)
September 2010
Clinical Antimicrobial
I:\9216dft.doc
08/31/10
Guidance for Industry
Chronic Hepatitis C Virus
Infection: Developing Direct-
Acting Antiviral Agents for
Treatment
Additional copies are available from:
Office of Communications, Division of Drug Information
Center for Drug Evaluation and Research
Food and Drug Administration
10903 New Hampshire Ave., Bldg. 51, rm. 2201
Silver Spring, MD 20993-0002
Tel: 301-796-3400; Fax: 301-847-8714; E-mail: druginfo@fda.hhs.gov
http://www.fda.gov/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/default.htm
U.S. Department of Health and Human Services
Food and Drug Administration
Center for Drug Evaluation and Research (CDER)
September 2010
Clinical Antimicrobial
TABLE OF CONTENTS
I.
INTRODUCTION
.............................................................................................................
1
II.
BACKGROUND
...............................................................................................................
2
III.
DEVELOPMENT PROGRAM
.......................................................................................
4
A.
General Considerations
.................................................................................................................
4
1.
Pharmacology/Toxicology Development Considerations
................................................................
4
2.
Nonclinical Virology Development Considerations
.........................................................................
5
a.
Mechanism of action
.................................................................................................................
5
b. Antiviral activity in cell culture
................................................................................................
5
c.
Resistance and cross-resistance
.................................................................................................
6
d. Combination antiviral activity
..................................................................................................
6
e.
Activity in animal models
.........................................................................................................
6
3.
Drug Development Population
.........................................................................................................
7
4.
Early Phase Clinical Development Considerations
.........................................................................
7
a.
First-in-human trials
..................................................................................................................
7
b. Phase 1b (proof-of-concept) trials
.............................................................................................
8
c.
Phase 2 trials and dose-finding
..................................................................................................
8
d. Combination therapy with multiple DAAs
.............................................................................
10
e.
Other phase 2 trial design considerations
................................................................................
11
5.
Efficacy Considerations
.................................................................................................................
11
6.
Safety Considerations
.....................................................................................................................
12
B.
Specific Efficacy Trial Design Considerations
...........................................................................
13
1.
Trial Design
...................................................................................................................................
13
2.
Trial Population
.............................................................................................................................
14
a.
Patient enrollment definition
...................................................................................................
14
b. Patient enrollment biopsy considerations
................................................................................
15
3.
Randomization, Stratification, and Blinding
..................................................................................
15
4.
Efficacy Endpoints
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5.
Trial Procedures and Timing of Assessments
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Statistical Considerations
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Analysis populations
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b. Efficacy analyses
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c.
Handling of missing data
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d. Interim analyses and data monitoring committees
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e.
Statistical analysis plan
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C.
Other Considerations
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Clinical Virology Considerations
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PK/PD Considerations
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Special Populations
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Hepatic impairment
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b. HIV/HCV co-infected patients
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Patients with decompensated cirrhosis
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d. Pediatric populations
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4.
Early Access/Treatment INDs
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GLOSSARY OF ACRONYMS
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REFERENCES
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1 Guidance for Industry1
2 Chronic Hepatitis C Virus Infection: Developing Direct3 Acting Antiviral Agents for Treatment
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5
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7
8
This draft guidance, when finalized, will represent the Food and Drug Administration’s (FDA’s) 9
current thinking on this topic. It does not create or confer any rights for or on any person and 10
does not operate to bind FDA or the public. You can use an alternative approach if the approach 11
satisfies the requirements of the applicable statutes and regulations. If you want to discuss an 12
alternative approach, contact the FDA staff responsible for implementing this guidance. If you 13
cannot identify the appropriate FDA staff, call the appropriate number listed on the title page of 14
this guidance. 15
16 17 18 19 I. INTRODUCTION 20 21 This guidance provides recommendations for the development of direct-acting antiviral 22 agents (DAAs) regulated within the Center for Drug Evaluation and Research at the Food 23 and Drug Administration (FDA) for the treatment of chronic hepatitis C (CHC) infection. 24 For the purpose of this guidance, we define direct-acting hepatitis C virus (HCV) 25 antivirals as agents that interfere with specific steps in the HCV replication cycle through 26 a direct interaction with the HCV polyprotein and its cleavage products. This guidance is 27 intended to serve as a focus for continued discussions among the review divisions, 28 pharmaceutical sponsors, the academic community, and the public.2 The organization of 29 the guidance parallels the development plan for a particular drug or biologic.3 30 31 This guidance does not address the development of immune-based agents for the 32 treatment of HCV infection such as new interferon products. Therapeutics without 33 antiviral mechanisms intended to mitigate or reverse clinical or pathophysiological 34 outcomes of CHC, such as prevention of hepatocellular carcinoma (HCC), reversal of 35 fibrosis, or treatment of acute hepatitis C, are not addressed in this guidance. 36
1 This guidance has been prepared by the Division of Antiviral Products in the Center for Drug Evaluation and Research (CDER) at the Food and Drug Administration.
2 In addition to consulting guidance documents, sponsors are encouraged to contact the division to discuss specific issues that arise during the development of DAAs.
3 For the purposes of this guidance, all references to drugs include both human drugs and therapeutic biological products unless otherwise specified.
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37 Additionally, general issues of clinical trial design or statistical analyses for HCV trials 38 are not addressed in this guidance. Those topics are addressed in the ICH guidances for 39 industry E9 Statistical Principles for Clinical Trials and E10 Choice of Control Group 40 and Related Issues in Clinical Trials.4 This guidance also does not contain details 41 regarding nonclinical safety and toxicology studies. Such studies for direct-acting HCV 42 antivirals generally should be conducted in standard animal models as described in the 43 guidance for industry Nonclinical Safety Evaluation of Drug or Biologic Combinations. 44 45 FDA’s guidance documents, including this guidance, do not establish legally enforceable 46 responsibilities. Instead, guidances describe the Agency’s current thinking on a topic and 47 should be viewed only as recommendations, unless specific regulatory or statutory 48 requirements are cited. The use of the word should in Agency guidances means that 49 something is suggested or recommended, but not required. 50 51 52 II. BACKGROUND 53 54 HCV is a small positive-strand RNA virus in the Flaviviridae family. Six viral 55 genotypes, numbered 1 to 6, have been identified; some have been divided into multiple 56 subtypes (e.g., genotype 1 subtypes 1a and 1b). In the United States, genotype 1 is the 57 most common (70 to 90 percent), followed by genotypes 2 and 3. Other genotypes occur 58 uncommonly in the United States, but may predominate in other parts of the world. 59 60 In the United States, HCV infection causes 20 percent of all cases of acute viral hepatitis 61 and 70 to 90 percent of all cases of HCC. Estimates show nearly 3.2 million Americans 62 are chronically infected with HCV. CHC is currently the leading indication in the United 63 States for liver transplantation, and predictive modeling suggests that without effective 64 treatment interventions significant increases in CHC-associated liver morbidity, 65 mortality, and health care costs are likely (Kim 2002). 66 67 Current treatment of CHC typically is a pegylated interferon administered in combination 68 with ribavirin (Peg-Interferon/RBV), often referred to in hepatitis C clinical trials as 69 standard of care (SOC). The goal of treatment is sustained virologic response (SVR), 70 defined as undetectable plasma HCV RNA at week 24 following treatment cessation 71 (SVR24). Total duration of current treatment depends on genotype, with longer 72 treatment durations needed to achieve SVR for genotypes 1 and 4 and shorter treatment 73 durations needed for genotypes 2 and 3. SVR rates in treatment-naive patients receiving 74 Peg-Interferon/RBV typically are in the range of 40 percent to 45 percent for viral 75 genotype 1 and are 70 percent to 80 percent for genotypes 2 and 3 (Ghany, Stradler, et al.
4 We update guidances periodically. To make sure you have the most recent version of a guidance, check the FDA Drugs guidance Web page at http://www.fda.gov/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/default.htm.
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76 2009).5 SVR rates for blacks and HIV co-infected patients with genotype 1 HCV are in 77 the range of 20 percent to 30 percent (in some studies less than 20 percent), which is 78 substantially lower than rates for whites and patients who are not co-infected. 79 80 On-treatment virologic measurements at early time points can predict the likelihood of 81 SVR and are often used to guide treatment duration. When treating with interferon-based 82 regimens, health care providers generally stop treatment if patients do not have at least a 83 2 log10 drop from baseline in HCV RNA at week 12 or do not have an undetectable HCV 84 RNA by week 24, because not meeting these interim virologic response criteria results in 85 a low likelihood of SVR. Three terms relating to on-treatment responses used in clinical 86 trials include: (1) rapid virologic response (RVR), meaning an undetectable HCV RNA 87 at 4 weeks of treatment; (2) complete early virologic response, meaning an undetectable 88 HCV RNA at week 12 of treatment; and (3) extended RVR, meaning an undetectable 89 HCV RNA at week 4 that persists through week 12. These measurements are sometimes 90 used to guide treatment duration strategies in clinical trials. 91 92 Even among patients who achieve SVR, liver injury may persist and hepatic 93 complications may occur; although the likelihood of hepatic complications appears to be 94 substantially reduced compared to patients who do not achieve SVR. Multiple 95 observational cohorts show correlations between SVR and improvements in clinical 96 outcomes of interest, such as development of HCC, hepatic events, fibrosis, and all-cause 97 mortality (Yoshida, Shiratori, et al. 1999; Yoshida, Arakawa, et al. 2002; Shiratori, Ito, et 98 al. 2005; Okanoue, Itoh, et al. 1999; Imai, Kawata, et al. 1998; Arase, Ikeda, et al. 2007; 99 Veldt, Heathcote, et al. 2007, Braks, Ganne-Carrie, et al. 2007; Bruno, Stroffolini, et al. 100 2007; Manos, Zhao, et al. 2009). Evaluating clinical outcomes from prospective, 101 randomized controlled clinical trials is challenging because of the difficulty of 102 maintaining patients on a randomized arm without intervening therapy for a sufficient 103 duration (many years) to identify late-occurring clinical events such as HCC. 104 105 Pegylated interferons and RBV are difficult to tolerate and have significant adverse event 106 profiles that limit treatment in many patients or result in substantial morbidity. 107 Therefore, new drugs are needed that increase SVR rates when added to current therapy, 108 that shorten the duration of interferon-based regimens, or that replace components of 109 current therapy in patients who cannot tolerate interferon or RBV. New drugs are also 110 needed to construct regimens in patients with decompensated cirrhosis and in patients 111 undergoing liver transplant. 112 113 Host factors, such as genetic polymorphisms, metabolic parameters, and viral factors 114 (i.e., genomic mutations), are being investigated for their roles in predicting response to 115 treatments for CHC. Recently, a genetic polymorphism near the IL-28B gene, encoding 116 interferon-l-3 (IFN-l-3), has been shown in several studies to predict an approximately 117 two-fold change in response to interferon-based treatment regimens in patients of
5 See also labeling information for PegIntron and Pegasys at http://www.accessdata.fda.gov/scripts/cder/drugsatfda/index.cfm?CFID=42688251&CFTOKEN=cea143f9 dc49c115-37E6D01E-0AF3-6971-CCAA04EECE6DE6A7.
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118 African-American and European ancestries (Ge, Fellay, et al. 2009). At least one test for 119 the IL-28B polymorphism is now available to physicians and for use in clinical protocols. 120 121 122 III. DEVELOPMENT PROGRAM 123 124 A. General Considerations 125 126 1. Pharmacology/Toxicology Development Considerations 127 128 Pharmacology/toxicology development for single direct-acting HCV antivirals should 129 follow existing guidances for drug development.6 130 131 Guidance suggests conducting nonclinical combination studies to support clinical trials 132 for combination drugs.7 However, similar to the approach used for HIV and oncology 133 drugs, we do not recommend that these nonclinical studies be conducted routinely for the 134 following reasons: 135 136 • In clinical practice, DAAs are likely to be used with multiple hepatitis C drugs, 137 including interferon and RBV and other DAAs, in multiple different 138 combinations; it would not be feasible to conduct animal studies for all potentially 139 relevant combinations 140 141 • Given the difficulty of conducting combination toxicologic studies that may 142 require multiple different drugs and multiple dose combinations, we believe that 143 nonclinical studies would be more interpretable and may offer more useful data 144 by looking at individual agents at multiple and higher doses 145 146 • Single- and multiple-dose drug-interaction trials in humans and in vitro metabolic 147 studies can screen for potential pharmacokinetic (PK) drug interactions that may 148 lead to safety issues 149 150 To support clinical trials evaluating 2 or more investigational DAAs for up to 90 days, we 151 recommend a minimum of 3 months repeat-dose nonclinical toxicity studies in a rodent 152 and nonrodent species for each individual agent. Longer term data on individual agents 153 (6-month rodent, 9-month nonrodent) can support longer duration combination clinical 154 trials, depending on the toxicity profile (see ICH M3(R2)). 155 156 Nonclinical combination studies of an investigational antiviral plus approved SOC (e.g., 157 Peg-Interferon/RBV) may not be needed unless data from nonclinical studies of an
6 See the ICH guidances for industry M3(R2) Nonclinical Safety Studies for the Conduct of Human Clinical Trials and Marketing Authorization for Pharmaceuticals and S6 Preclinical Safety Evaluation of Biotechnology-Derived Pharmaceuticals.
7 See the guidance for industry Nonclinical Safety Evaluation of Drug or Biologic Combinations.
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158 investigational antiviral drug suggest a potential for increased or synergistic toxicity with 159 the approved therapeutic agents. 160 161 2. Nonclinical Virology Development Considerations 162 163 DAAs for the treatment of CHC should be tested in cell culture for antiviral activity 164 before submission of an initial investigational new drug application (IND). Information 165 about pre-investigational new drug testing and information regarding appropriate 166 nonclinical assays is available from the FDA.8 Additional recommendations for general 167 antiviral drug development can be found in the guidance for industry Antiviral Product 168 Development — Conducting and Submitting Virology Studies to the Agency. 169 170 a. Mechanism of action 171 172 The mechanism by which a DAA exhibits anti-HCV activity should be investigated in 173 studies that include evaluation of the effect of the agent on relevant stages of the virus life 174 cycle. Mechanism of action investigations should include appropriate controls for 175 assessing the specificity of anti-HCV activity, which may include assessments of activity 176 against HCV proteins that are not targeted by the candidate agent, relevant host proteins, 177 or other viruses. 178 179 b. Antiviral activity in cell culture 180 181 The antiviral activity of a new agent should be characterized in cell culture to identify a 182 target plasma concentration for evaluation in HCV-infected patients. Antiviral activity of 183 candidate agents targeting nonstructural components should be assessed using HCV 184 genotype 1a- and 1b-derived replicon systems, and a 50 percent effective concentration 185 (EC50) determined. Nonclinical studies should include assessments of antiviral activity 186 against the major HCV genotypes and subtypes. Assessments of antiviral activity against 187 replication models using HCV components derived from multiple clinical isolates are 188 also recommended, because antiviral activity can vary for strains within each subtype. If 189 differences in susceptibility are observed for different clinical isolates within the same 190 viral genotype or subtype, additional genotypic and phenotypic characterizations should 191 be conducted to identify genetic polymorphisms that may affect HCV susceptibility to the 192 new agent. 193 194 The antiviral activity of agents that target HCV entry functions can be evaluated using 195 HCV pseudoparticle systems. Assessments of antiviral activity against HCV grown in 196 cell culture are recommended for any anti-HCV agent when appropriate. The cytotoxic 197 effects of the agent should be quantified directly in the cells used for assessing anti-HCV 198 activity, and a 50 percent cytotoxic concentration (CC50) and a therapeutic index should 199 be calculated. Cytotoxicity should also be assessed using various cell lines and primary 200 cells cultured under proliferating and nonproliferating conditions. Sequestration of the
8 See the FDA Web site http://www.fda.gov/Drugs/DevelopmentApprovalProcess/HowDrugsareDevelopedandApproved/Approval Applications/InvestigationalNewDrugINDApplication/Overview/ucm077546.htm.
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201 agent by serum proteins should also be assessed and a serum-adjusted EC50 value 202 determined. We recommend evaluation of the agent’s antiviral activity at different 203 concentrations of human serum and extrapolation to a 100 percent human serum EC50 204 value. 205 206 c. Resistance and cross-resistance 207 208 The ability of HCV to develop resistance to a DAA when subjected to drug pressure 209 should be examined in appropriate cell culture models. Amino acid or nucleotide 210 substitutions associated with the development of resistance to the candidate agent should 211 be determined and validated by introducing the changes into the HCV genome and 212 determining the conferred fold-shift in susceptibility using appropriate cell culture and/or 213 biochemical assays. Results from these studies should be used to: (1) determine whether 214 the genetic barrier for resistance development is high or low; (2) predict whether the 215 genetic barrier for resistance may vary as a function of concentration of the new agent; 216 (3) reveal potential resistance pathways and the potential for cross-resistance with other 217 anti-HCV agents; and (4) support the agent’s hypothesized mechanism of action. 218 219 Resistance studies should include evaluation of the potential for cross-resistance, both to 220 approved agents and to agents in development, particularly focusing on those in the same 221 drug class. Although the mechanism of action for RBV remains unclear, RBV should be 222 included in assessments of cross-resistance for inhibitors that target the NS5B RNA223 dependent RNA polymerase. 224 225 d. Combination antiviral activity 226 227 Most, if not all, DAAs for HCV will be used to treat CHC in combination with other 228 approved drugs. Early in development, cell culture combination antiviral activity 229 relationships of the new agent and pegylated interferons and the new agent and RBV 230 should be characterized to determine whether the combination antiviral activity is 231 additive, synergistic, or antagonistic. Additional combination antiviral activity studies 232 with other candidate anti-HCV agents should be conducted if future combination therapy 233 with other agents is anticipated. For all combination antiviral activity assessments, 234 sponsors should provide combination index values when the two agents are combined at 235 or near their individual EC50 values, and studies should include controls for cytotoxicity. 236 Combination antiviral activity relationships for HIV and HCV agents with similar 237 mechanisms of action (e.g., nucleoside analogue polymerase/reverse-transcriptase 238 inhibitors, protease inhibitors) should also be assessed before testing combinations of the 239 agents in HIV/HCV co-infected patients. 240 241 e. Activity in animal models 242 243 Demonstration of anti-HCV activity in an animal model is not needed. However, if such 244 studies are conducted and provided in support of an anti-HCV therapy program, reported 245 data should include the HCV genotype/subtype used, time course plots of viral load data
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246 for each animal, and an assessment of resistance development that includes monitoring 247 the persistence of resistant virus in the absence of anti-HCV treatment. 248 249 3. Drug Development Population 250 251 Overall drug development programs should include a broad population as appropriate for 252 the characteristics of the antiviral agent. However, a DAA may have differential activity 253 against different HCV genotypes or subtypes; therefore, development can be targeted to a 254 specific genotype (e.g., genotype 1 versus genotype 2 or 3). We recommend including 255 patients diagnosed with compensated cirrhosis in phase 2 and phase 3 trials. Also, we 256 encourage the study of combinations of direct-acting HCV antivirals in patients with the 257 greatest need for new agents, such as patients who cannot tolerate interferon, patients for 258 whom interferon is contraindicated, transplant patients, and patients with decompensated 259 cirrhosis. DAAs can be studied in combination with other DAAs and with or without 260 SOC in HIV co-infected patients as soon as appropriate based on the availability of data. 261 Trials in the above-mentioned subgroups may need to be supported by preliminary data 262 from trials to define safety and pharmacokinetics, such as hepatic impairment trials and 263 drug-drug interaction trials (e.g., antiretrovirals for HIV, immunosuppresants for 264 transplant). 265 266 CHC is a disease that is present worldwide and clinical trials typically are conducted 267 internationally. However, trials should include adequate U.S. patient representation to 268 ensure applicability of trial results to the U.S. population. An adequate representation of 269 males and females, races, ages, and weights is recommended during drug development, 270 especially in phase 3 trials. Because race (e.g., black, Asian) and ethnicity (e.g., Latino) 271 affect response rates to interferon-based regimens, it is important to ensure that there is 272 sufficient diversity in clinical trial demographics to conduct meaningful analyses of such 273 groups. Furthermore, in addition to viral genotypes, host genotypes are emerging as 274 correlates of clinical response to antivirals and may partially explain differences in 275 response rates by race; therefore, collection of patient DNA is an important 276 consideration.9 277 278 4. Early Phase Clinical Development Considerations 279 280 The early clinical evaluation of new DAAs should follow a rational plan to provide 281 sufficient data to establish preliminary safety and activity to support phase 3 trials. 282 283 a. First-in-human trials 284 285 In general, we recommend single- and/or multiple-ascending-dose trials in healthy adult 286 subjects to assess safety and pharmacokinetics for the first-in-human trials. However, 287 single-dose and short multiple-dose PK trials (see below) can also be conducted in HCV288 infected patients, particularly if nonclinical data suggest a drug may be genotoxic or 289 otherwise unacceptable for studies in healthy volunteers.
9 See the guidance for industry Pharmacogenomic Data Submissions.
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290 291 b. Phase 1b (proof-of-concept) trials 292 293 The first proof-of-concept trial (meaning a trial in HCV-infected patients that 294 demonstrates initial activity as measured by reductions in HCV RNA from baseline 295 levels) should be a repeat-dose, randomized, dose-ranging, monotherapy trial, of 296 approximately 3 days duration, with collection of intensive PK, safety, and HCV RNA 297 decay data. Doses selected for phase 1b should be predicted to provide plasma drug 298 exposures expected to exceed, by several-fold, the protein binding-adjusted, cell culture 299 EC50 value of the agent for the relevant HCV genotype/subtype. Choice of doses should 300 also take into account safety margins identified in animal toxicology studies and in any 301 trials conducted in healthy volunteers. 302 303 Monotherapy exceeding 3 days is not recommended because data indicate resistant virus 304 is rapidly selected during monotherapy dosing with some DAA drug classes. 305 Furthermore, 3 days of monotherapy with a directly targeting anti-HCV agent is usually 306 sufficient for establishing proof of concept and for initial dose exploration. Selection of 307 resistance may limit the future utility of the new agent as well as other agents with similar 308 resistance pathways. In most cases, longer durations of monotherapy with directly 309 targeting anti-HCV agents are not appropriate because of resistance concerns, but can be 310 considered on a case-by-case basis depending on the characteristics of the individual 311 agent. In addition to limiting the duration of monotherapy, we recommend that phase 1 312 trials of initial activity be conducted in patients with CHC who are naïve to previous anti313 CHC therapy (including the agent under investigation), and who have minimal fibrosis 314 and no significant co-morbidities. Following demonstration of safety and antiviral 315 activity in treatment-naïve patients, sponsors can plan additional trials in treatment316 experienced patients. 317 318 Results from proof-of-concept trials can be used to guide dose selection for subsequent 319 phase 2 trials in which DAAs are studied for longer durations as part of a combination 320 regimen. We recommend that sponsors conduct mechanistic modeling of the 321 concentration-viral kinetics and the concentration-safety profile from phase 1 trials to 322 predict the most active and tolerable doses for study in phase 2. The mechanistic viral 323 kinetic model should describe time-dependent changes in HCV infection and the effect of 324 drug concentrations (Neumann, Lam, et al. 1998). The model should also include 325 components to describe virologic breakthrough, relapse, and long-term viral response 326 (e.g., SVR) to inform dose selection and treatment duration. In general, the model should 327 be used to inform dose selection and to reduce the risk of selecting for resistant virus 328 because of subtherapeutic exposure. 329 330 c. Phase 2 trials and dose-finding 331 332 A goal of early phase 2 trials is to begin to characterize the optimal dose and duration of 333 the DAA as part of combination regimens with regard to both activity and safety. 334
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335 The most straight-forward design for early phase 2 is a randomized controlled trial of 336 several doses of a DAA added to Peg-Interferon/RBV compared to a standard-of-care 337 regimen (consisting of Peg-Interferon/RBV). In general, trial patients should receive a 338 full course of treatment with the Peg-Interferon/RBV component (24 to 48 weeks 339 depending on early treatment responses); however, the DAA component can be 340 administered for shorter durations (e.g., 12 weeks, depending on results from phase 1b). 341 The dosing duration of the investigational agent in phase 2 trials should be based on 342 scientific and clinical rationale and not limited in duration only because long-term animal 343 toxicology studies have not been completed. 344 345 The U.S.-approved Peg-Interferon/RBV labels for treatment of HCV genotype 1 HCV 346 recommend 48 weeks of therapy; although in practice many clinicians shorten the course 347 for patients who have HCV RNA levels below the limit of detection at week 4 of 348 treatment. At present, the optimal duration of dosing a third drug in combination with 349 Peg-Interferon/RBV is not known and is likely to vary depending on characteristics of the 350 investigational agent and treatment population. Thus, various durations of treatment can 351 be evaluated in clinical trials. However, we generally recommend that phase 2 trials 352 include at least one treatment arm that evaluates 48 weeks of treatment with all 353 components of a regimen unless antiviral activity or safety data support a rationale for 354 shorter durations of the DAA component of the regimen. Evaluating shorter durations of 355 a regimen or a component of the regimen can also be accomplished by incorporating a 356 second randomization to assess treatment duration in those patients who have 357 demonstrated early virologic suppression. For example, one treatment strategy can allow 358 patients who reach undetectable HCV RNA by week 4 (RVR) and maintain undetectable 359 HCV RNA level at week 12 (extended RVR) to be re-randomized to receive a regimen of 360 24 versus 48 weeks in duration. Patients who do not attain extended RVR would receive 361 48 weeks of therapy in this example. 362 363 We recommend that sponsors conduct their first phase 2 combination trials with Peg364 Interferon/RBV in treatment-naïve patients as opposed to starting dose-finding in 365 treatment-experienced patients. Giving suboptimal doses to treatment-experienced 366 patients can further increase emergence of resistance and incomplete virologic response 367 to a DAA in combination with Peg-Interferon/RBV and this could jeopardize future 368 treatment regimens for those individuals. 369 370 Sustained virologic response should be the primary endpoint of the phase 2 trials; 371 however, analyses of 12 weeks of safety and antiviral activity data from the first 372 combination trial with Peg-Interferon/RBV in treatment-naïve patients can be used to 373 design larger phase 2b dose comparison trials to further characterize optimal dosing in 374 broader populations, including both treatment-naïve and treatment-experienced patients. 375 376 To provide the most meaningful comparisons for further development of a DAA, we 377 recommend phase 2 trial designs allow for direct comparisons between treatment arms 378 with respect to dose, strategy, and duration. For example, if two doses are evaluated, 379 both treatment doses should be evaluated for the same duration of therapy. 380
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381 Because the presence of an IL-28B genetic polymorphism has been shown to predict 382 substantial treatment response differences among patients receiving Peg-Interferon/RBV, 383 an effort should be made to collect samples for IL-28B testing at baseline to reduce the 384 potential for confounding in trial analyses. For example, in smaller dose-finding trials, 385 treatment arm imbalances in patients with the IL-28B polymorphism can confound 386 interpretation of trial results if sponsors do not consider the potential effect of this 387 predictive marker on treatment outcome. Sponsors should consider stratifying based on 388 IL-28B when DAAs are combined with Peg-Interferon/RBV in phase 2 and phase 3 389 trials. 390 391 d. Combination therapy with multiple DAAs 392 393 We encourage trials of DAAs with and without Peg-Interferon/RBV, depending on the 394 patient population. Trials of combinations of DAAs in patients who cannot tolerate 395 interferon or for whom interferon is contraindicated may address an unmet medical need. 396 Based on HCV replication dynamics in infected patients (Perelson 2009), the error-prone 397 nature of HCV genome replication, and the fact that the activity of a DAA is often 398 reduced by a single amino acid substitution in the drug target, multiple DAAs are needed 399 to suppress all pre-existing and emerging drug resistant variants to achieve SVR. At 400 present it is not known whether regimens that do not include interferon can produce SVR. 401 402 Ideally, agents with different mechanisms of action should be considered for combination 403 use. The information recommended to support combination trials using DAAs without 404 interferon and RBV includes: 405 406 • Combination antiviral activity data from cell culture 407 408 • Resistance and cross-resistance patterns for each agent in the combination 409 410 • Anti-HCV activity data from clinical trials (from short-term monotherapy trials or 411 from dose-finding in combination with Peg-Interferon/RBV) 412 413 • Some human safety data on each agent 414 415 • Justification for proposed doses based on clinical trials or other sources to indicate 416 doses chosen are likely to provide reasonable anti-HCV activity 417 418 • Drug-drug interaction data if the metabolism profiles suggest an interaction 419 potential between agents in the combination regimen 420 421 Some examples of potential designs for initial trials of combinations of DAAs include but 422 are not limited to the following: 423 424 • Randomized, controlled trials that compare short durations (less than 2 weeks) of 425 multiple DAAs in treatment-naïve patients followed by a full course of Peg426 Interferon/RBV either with or without one or more of the DAAs evaluated in the
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427 first 2 weeks. An approved Peg-Interferon/RBV regimen can be used as a control 428 arm. 429 430 • Randomized, controlled trials that compare several different dosing combinations 431 of multiple DAAs given for longer durations in treatment-naïve or -experienced 432 patients. This type of design includes frequent HCV RNA monitoring and 433 stopping rules for loss or lack of antiviral response. When enrolling treatment434 naïve patients or treatment-experienced patients who can tolerate interferon and 435 RBV, protocols can specify adding interferon and RBV to the DAA regimen after 436 a specified time point (e.g., 6 weeks) or at any other time if virologic rebound or 437 lack of complete virologic response is determined. 438 439 • A single-arm trial evaluating multiple doses of combination therapy before liver 440 transplant to study the overall antiviral effect before liver transplant and 441 potentially the effect on preventing infection of the transplanted liver. Response 442 rates can be compared to historical controls because transmission of HCV to a 443 transplanted liver in this setting is universal (Gane 2008), such that demonstrating 444 lack of infection in a substantial proportion of allograft recipients is meaningful. 445 446 Sponsors are encouraged to discuss with the FDA proposed development plans for 447 combination therapy of two or more DAAs. 448 449 e. Other phase 2 trial design considerations 450 451 Phase 2 trials can also be used to explore alternative dosing strategies of a DAA in 452 combination with other agents before confirmation of alternative dosing strategies in 453 larger phase 3 trials. Detailed rationale for an alternative dosing strategy should be 454 included with a phase 2 protocol submission. One example of an alternative dosing 455 strategy is a lead-in period with Peg-Interferon/RBV (before initiation of the new agent 456 as part of a three-drug therapy). One arm containing a lead-in period with Peg457 Interferon/RBV can be compared to another arm in which all drugs in the regimen were 458 started simultaneously. In theory, a lead-in strategy may be beneficial before starting a 459 DAA with a low genetic barrier to resistance because Peg-Interferon/RBV may reach a 460 steady-state by the time the new agent is added, reducing the possibility of combining the 461 agent in the setting of subtherapeutic Peg-Interferon/RBV exposures. The effects of 462 variations in dosing of a combination regimen, such as lead-in periods, can be explored in 463 phase 2 and confirmed in phase 3. 464 465 5. Efficacy Considerations 466 467 We recommend that sponsors analyze and provide summaries of SVR outcome data 468 (SVR12 and SVR24) from phase 2 to demonstrate that treatment responses are durable 469 and to allow for sample size calculations for phase 3 trials. 470 471 Sponsors can submit an NDA to gain approval of a drug in a single population, either 472 treatment-naïve or treatment-experienced patients. Such an application should include at
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473 least two adequate and well-controlled trials conducted in the proposed population 474 intended for labeling. Alternatively, sponsors can choose to pursue an indication for both 475 treatment-naïve and -experienced patients. In this circumstance, the NDA should contain 476 at least one adequate and well-controlled phase 3 trial in each patient population, with 477 adequate supporting data from phase 2 trials. 478 479 Trial designs for combinations of investigational DAAs without interferon and RBV 480 should include provisions for demonstrating that each component of the combination 481 therapy contributes to the desired effect. Establishing the contribution of each 482 component can be accomplished using factorial designs or modified factorial designs; 483 however, we acknowledge that factorial designs in which patients are randomized to only 484 one new DAA may not be appropriate because of emergence of resistance. As an 485 alternative to factorial designs, sponsors can show a DAA’s contribution toward efficacy 486 of a multiple DAA combination regimen using other types of data. Examples of data 487 supporting contribution of efficacy include but are not limited to the following: 488 489 • Cell culture data showing that DAA combinations slow or prevent the emergence 490 of resistance compared to single agents. 491 492 • Clinical trial data showing the efficacy of each new DAA in combination with 493 interferon and RBV. 494 495 • Comparisons of viral load reductions of short-term monotherapy trials (e.g., 3-day 496 trials) with viral load reductions of combination therapy in the same trial or across 497 other short-term trials. In this example, short-term viral load reductions in 498 patients given combination therapy with two DAAs should be substantially 499 greater than that observed in patients given the single agents. 500 501 • Early phase 2 clinical trial data showing that DAA combinations prevent or 502 reduce emergence of resistance. 503 504 Sponsors should consult 21 CFR 300.50 regarding combining drug products in a single 505 dosage form. 506 507 HCV treatment development plans may be eligible for consideration under 21 CFR part 508 312, subpart E, Drugs Intended to Treat Life-Threatening and Severely-Debilitating 509 Illnesses, fast track,10 or priority review if the specifics of the development plan justify 510 such an approach. 511 512 6. Safety Considerations 513 514 In general, we recommend that initial marketing applications for drugs intended to treat 515 CHC in patients without decompensated cirrhosis contain a safety database of
10 See the guidance for industry Fast Track Drug Development Programs — Designation, Development, and Application Review.
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516 approximately 1,000 to 1,500 patients exposed to the proposed dose and duration of 517 treatment. However, if significant safety signals emerge during drug development, the 518 safety database may need to be increased or specific safety studies may need to be 519 conducted. 520 521 For an indication in patients with decompensated cirrhosis or in patients who generally 522 have a high risk of morbidity and few if any treatment options, a safety database of 523 approximately 500 patients administered the DAA for the proposed dose and duration 524 may be sufficient for filing an NDA. We encourage sponsors to discuss their proposed 525 safety database before submitting an NDA. On occasion, specific findings in nonclinical 526 or clinical development may indicate the need for a database that is larger or longer in 527 duration to adequately evaluate potential drug toxicity. 528 529 We recommend that sponsors provide controlled and comparative safety data. Safety 530 data from uncontrolled protocols or treatment IND protocols may be useful, but often 531 lack the degree of detailed reporting obtained in controlled clinical trials. Moreover, the 532 assessment of causal relationships between a drug and an adverse event is more difficult 533 when relying on uncontrolled safety data and spontaneously occurring events or events 534 related to concurrent treatment or underlying illness may be attributed to the new drug. 535 536 B. Specific Efficacy Trial Design Considerations 537 538 1. Trial Design 539 540 Until the first DAA is approved, the recommended, and most straight-forward, design for 541 initial registration of a DAA is demonstration of superiority as an add-on to SOC, Peg542 Interferon/RBV, in a blinded comparison to placebo plus SOC. In the future, a 543 superiority design also can include a new drug as part of a four-agent regimen compared 544 to a three-agent regimen. Alternatively, an active-controlled noninferiority trial design 545 could be appropriate, comparing a new DAA plus Peg-Interferon/RBV to another 546 approved DAA (control) plus Peg-Interferon/RBV. The latter design is dependent on the 547 ability to define the contribution of the new active control to the Peg-Interferon/RBV 548 treatment so that a stringent noninferiority margin can be calculated. Sponsors 549 considering a noninferiority trial design should discuss in advance with the FDA 550 justification of the noninferiority margin, trial design, and the data analysis plan.11 551 552 Patients who achieve SVR should be followed for at least 3 years in larger phase 2 or 553 phase 3 trials to: (1) ensure durability of response; (2) determine whether subsequent 554 detection of HCV RNA represents outgrowth of pre-existing virus versus re-infection; 555 and (3) evaluate development of progressive liver disease and/or HCC. Long-term 556 follow-up can be provided as part of a postmarketing commitment following the initial 557 application.
11 For more information, see the draft guidance for industry Non-Inferiority Clinical Trials. When final, this guidance will represent the FDA’s current thinking on this topic. For the most recent version of a guidance, check the FDA Drugs guidance Web page at http://www.fda.gov/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/default.htm.
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558 559 2. Trial Population 560 561 a. Patient enrollment definition 562 563 To be enrolled in a trial, patients should have CHC as documented by being tested: 564 565 • Positive for anti-HCV antibody, HCV RNA, or an HCV genotype at least 6 566 months before screening, and positive for HCV RNA and anti-HCV antibody at 567 the time of screening; or 568 569 • Positive for anti-HCV antibody and HCV RNA at the time of screening with a 570 liver biopsy consistent with chronic HCV infection (or a liver biopsy performed 571 before enrollment with evidence of CHC disease, such as the presence of fibrosis) 572 573 In addition to documentation of CHC, treatment-experienced patients should have 574 complete documentation of prior treatment history (including but not limited to 575 compliance with previous therapy and reasons for discontinuation), because these factors 576 may affect their response to retreatment. For the purpose of trial enrollment, the 577 following definitions are used to define the treatment experience of CHC patients, which 578 are based on previous responses to Peg-Interferon/RBV.12 579 580 • Naïve: received no prior therapy for HCV (including interferon or pegylated 581 interferon monotherapy) 582 583 • Null Responder13: less than 2 log10 reduction in HCV RNA at week 12 of a Peg584 Interferon/RBV 585 586 • Partial Responder: greater than or equal to 2 log10 reduction in HCV RNA at 587 week 12, but not achieving HCV RNA undetectable at end of treatment with a 588 Peg-Interferon/RBV 589 590 • Responder Relapser: HCV RNA undetectable at end of treatment with a 591 pegylated interferon-based regimen, but HCV RNA detectable within 24 weeks of 592 treatment follow-up 593 594 Note that HCV RNA undetectable for previous treatment response should have 595 been based on an assay that was considered sensitive at the time of treatment.
12 Patients who previously received interferon monotherapy or nonpegylated interferons plus RBV will be a diminishing proportion presenting for future trials. These patients can be categorized separately.
13 Other definitions for null response have been proposed, such as less than 1 log10 IU/mL decline in HCV RNA at week 4 of treatment. However, failure to achieve a greater than 2 log10 IU/mL HCV RNA decline at week 12 has typically been used as a treatment futility criterion and use of a null response definition of viral reduction less than 1 log10 IU/mL at week 4 causes a gap in classification for individuals with a viral load reduction greater than 1 log10 at week 4 but less than 2 log10 reduction at week 12.
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596 597 b. Patient enrollment biopsy considerations 598 599 Baseline biopsies can help to establish CHC diagnosis and can be useful for making 600 correlations between the amount of baseline fibrosis and subsequent treatment outcomes 601 such as SVR and occurrence of treatment-related adverse events. Correlations between 602 baseline fibrosis and efficacy or safety outcomes can provide useful information in 603 labeling. Sponsors should have a sufficient number of baseline biopsies throughout drug 604 development to explore correlations between fibrosis and outcomes. We recommend the 605 following regarding enrollment biopsies throughout drug development: 606 607 • For phase 1 trials in CHC patients and early phase 2 trials intended to evaluate 608 pharmacokinetics/pharmacodynamics (PK/PD) or initial efficacy and safety, a 609 liver biopsy may not be needed as long as patients fulfill the criteria for CHC 610 infection as described in the section above. 611 612 • For later phase 2 trials and phase 3 treatment-naïve trials, we recommend biopsies 613 within 2 to 3 years before enrollment. If cirrhosis has been previously 614 demonstrated on a biopsy, then biopsies obtained more than 3 years before 615 enrollment need not be repeated. 616 617 • For later phase 2 and 3 trials in treatment-experienced patients, a biopsy within 2 618 to 3 years may not be needed for trial enrollment; however, documentation of a 619 prior biopsy showing histological evidence of CHC should be available for 620 review. 621 622 • Biopsies can be waived for patients who would be placed at risk from the 623 procedure, such as patients with bleeding disorders. Inability to do a liver biopsy 624 should not exclude patients from a trial. 625 626 Noninvasive measures of hepatic fibrosis and disease activity assessments using 627 biochemical or scanning measurements are not considered validated and should not be a 628 substitute for the histological information yielded by liver biopsy. 629 630 3. Randomization, Stratification, and Blinding 631 632 We encourage sponsors to conduct double-blind trials whenever feasible. For add-on 633 superiority trials of a new DAA plus SOC compared to SOC alone, patients randomized 634 to SOC should receive a matching DAA placebo. It is appreciated that endpoints in these 635 trials are objective, but other aspects of the trial can be influenced by knowledge of 636 treatment assignment. In open-label protocols, patients may be more likely to drop out of 637 the trial if they know they are not receiving the new treatment or investigators could 638 provide different levels of encouragement to continue. 639 640 Sponsors should consider stratification of patients by important baseline factors such as 641 IL-28B polymorphisms, viral load (high or low), HCV genotype/subtype, and cirrhosis,
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642 because these baseline factors are predictive of SVR depending on the regimen and 643 population studied. In international trials, patients should be stratified by geographic 644 area. 645 646 4. Efficacy Endpoints 647 648 The primary endpoint for phase 3 studies should be SVR at 24 weeks after completion of 649 a scheduled course of therapy (SVR24). Viral RNA clearance should be measured using 650 a sensitive and specific quantitative assay. Before initiation of clinical trials, sponsors 651 should provide in their development plans the name and performance data for the assay 652 proposed for measuring HCV RNA viral load. 653 654 5. Trial Procedures and Timing of Assessments 655 656 Recommended key time points for measuring viral RNA are at weeks 4, 12, 24, and 48 or 657 at the end of therapy (which may occur at 24 or 48 weeks). Viral measurements at week 658 12 and 24 have been critical for deciding whether a full course of interferon/RBV is 659 justified. Week 4 and 12 measurements can be used in protocol decision making for 660 determining duration of a DAA or a regimen. 661 662 6. Statistical Considerations 663 664 a. Analysis populations 665 666 All patients who are randomized and receive at least one dose of assigned therapy during 667 the trial should be included in the primary efficacy analysis. If a substantial proportion of 668 patients exit the trial after randomization but before receiving treatment or if there is an 669 imbalance between treatment arms in the number of such patients, then sensitivity 670 analyses can be conducted imputing all or a proportion of those who exited as treatment 671 failures. 672 673 b. Efficacy analyses 674 675 The primary analysis endpoint should be SVR24, which measures the presence or 676 absence of viral RNA 24 weeks after completing a protocol-defined treatment course, and 677 this analysis determines whether effectiveness has been demonstrated.14 The primary 678 analysis should be adjusted for at least one or two of the most important covariates (e.g., 679 baseline HCV genotype, screening HCV RNA or IL-28B polymorphism). The covariates 680 that will be included in the primary analysis should be prespecified in the protocol. 681 682 For subgroup analyses, the analysis of SVR24 should be performed within important 683 demographic and baseline characteristics (e.g., geographic region (U.S., non-U.S.), sex, 684 race, age group, HCV genotype, screening serum HCV RNA, IL-28B status, baseline
14 Patients who discontinue therapy, for whatever reason, before the protocol-defined treatment duration can still be considered a responder if they have confirmed absence of HCV RNA 24 weeks after the originally planned treatment duration.
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685 weight, baseline body mass index, baseline alanine aminotransferase (ALT), baseline 686 liver histology, baseline fibrosis, and prior response to interferon/RBV-based regimens). 687 The purpose of these subgroup analyses basically is to evaluate the consistency of the 688 SVR24 endpoint result across these subgroups. It is important to recognize, however, 689 that simply by chance a hypothetical drug that has a homogeneous overall effect in a trial 690 population will almost invariably show statistically significant effects in some subgroups 691 and not in others in any given trial. Therefore, such subgroup results should be 692 interpreted with caution. 693 694 For meaningful subgroup analyses in treatment-experienced trials there should be 695 adequate representation from null responders, partial responders, and responder relapsers, 696 as appropriate for each drug based on activity observed in phase 2 data (phase 2 data may 697 suggest that it is futile to study certain categories of nonresponders in phase 3). 698 699 Secondary endpoints can include: 700 701 • Normalization of ALT levels 702 703 • The proportion of patients with RVR (undetectable HCV RNA after 4 weeks of 704 treatment) 705 706 • The proportion of patients with complete early virologic response (undetectable 707 HCV RNA after 12 weeks of treatment) 708 709 • The proportion of patients with undetectable levels of HCV RNA at the end of 710 treatment and 12 weeks after the end of treatment 711 712 • Relapse rates at 12 and 24 weeks after the end of treatment 713 714 However, secondary endpoints are not sufficient to support efficacy in the absence of an 715 effect on the primary endpoint. The protocol should propose a multiple testing strategy 716 for secondary endpoints that adjust for multiplicity to be applied after the result for the 717 primary endpoint is significant. 718 719 Patients who stop treatment because they did not completely suppress HCV RNA or had 720 rebound of HCV RNA after complete suppression should be regarded as failures in all 721 analyses. For patients who discontinue treatment early, sponsors should collect 722 information to determine if these patients switched treatments or added additional 723 therapy. This information can be used to understand reasons for discontinuation and how 724 patients will be included in the analysis. 725 726 c. Handling of missing data 727 728 For the primary analysis, sponsors should consider patients not to have achieved an SVR 729 if the patients discontinue from a trial before the end of the scheduled 24 week follow-up
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730 period and if the patients have missing HCV RNA values at the end of the scheduled 24 731 week follow-up period. 732 733 Sponsors should make every attempt to limit loss of patients from the trial, and when the 734 loss is unavoidable, to collect information that can help explain the cause of the loss and 735 the final status of the patient. Analyses excluding patients with missing data or other 736 post-treatment outcomes can be biased because patients who do not complete the trial 737 may differ substantially in both measured and unmeasured ways from patients who 738 remain in the trial. 739 740 A range of sensitivity analyses should be performed to demonstrate that the primary 741 analysis is robust to discontinuation and noncompliance. Sensitivity analyses can be 742 performed using various methods for imputing missing post-treatment virologic results at 743 24 weeks of follow-up. Examples include but are not limited to using results from any 744 available last post-treatment week in place of the 24-week follow-up visit or treating a 745 percentage of missing data as successes or failures based on the overall results in which 746 post-treatment data are available. 747 748 We recommend that sponsors collect detailed data on drug-adherence and confirmation 749 of reasons for discontinuation (e.g., opportunity to enter another trial offering a promising 750 new treatment, death or events leading to death, disease progression, adverse events, loss 751 to follow-up, withdrawal of consent, noncompliance, pregnancy, protocol violations, not 752 discontinued or not known to be discontinued but data were missing at the final visit). 753 The underlying reasons for discontinuation should be interpreted. For example, the 754 statistical analysis should include the number of patients who withdrew consent or were 755 lost to follow-up, or who had adverse events (e.g., nausea and diarrhea) that could have 756 been related to the treatment they were taking. 757 758 d. Interim analyses and data monitoring committees 759 760 If interim (or futility) analyses are performed, these analyses should be specified in the 761 statistical analysis plan (SAP). The purpose of the interim analysis should be stated in 762 the SAP. 763 764 The SAP should include provisions that ensure the interim analysis does not compromise 765 trial integrity. Sponsors should refer to ICH E9 when considering the use of interim 766 analyses in clinical trials. 767 768 Sponsors should consider using a data monitoring committee for phase 3 trials evaluating 769 treatments for CHC, particularly if there are potential safety issues with one or more 770 treatment arms. A detailed charter with the composition of the committee members and 771 the operational details should be provided for review.15 772
15 See the guidance for clinical trial sponsors Establishment and Operation of Clinical Trial Data Monitoring Committees.
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773 e. Statistical analysis plan 774 775 Before initiation of any phase 2b trial (larger phase 2 trial intended to be supportive of 776 efficacy for registration) or phase 3 trial, we recommend sponsors provide a detailed 777 SAP. The SAP can be either a separate document or be within the protocol. The SAP 778 should be considered as part of the protocol and ideally should be finalized together with 779 the protocol before patient enrollment. The SAP should have details on endpoint 780 ordering, the analysis population, the structure of statistical hypotheses to be tested, 781 methods and statistical models of analyses including the mathematical formulations, level 782 of significance or alpha-level, alpha adjustments for multiple comparisons and interim 783 analyses, and any planned covariates for the analyses. It is possible to modify an SAP as 784 long as the trial remains blinded, but sponsors should recognize that a detailed discussion 785 may be needed concerning data access and appropriate firewalls for maintaining the 786 integrity of the blind. 787 788 It is important that the SAP prospectively identify the covariates to be used in the 789 analysis. It is also important that the number of covariates be kept to a minimum and 790 limited to those that are expected to strongly influence outcome. 791 792 Center-by-treatment interaction should be investigated and reported to assess consistency 793 of the efficacy results. 794 795 C. Other Considerations 796 797 1. Clinical Virology Considerations 798 799 Proof-of-concept and efficacy trials should assess the development of HCV genotypic 800 resistance to the investigational agent. Resistance testing should be performed for 801 patients who demonstrate virologic breakthrough (defined as a greater than or equal to 1 802 log10 increase in HCV RNA above nadir, or detectable HCV RNA, while on treatment, 803 after an initial drop to below detection), an incomplete antiviral response (e.g., detectable 804 HCV RNA at end of treatment), a slow or plateau viral load decay phase, or virologic 805 relapse after treatment cessation. Any changes, including mixtures, in the amino acid 806 coding sequence of the targeted genome region present in on-treatment or follow-up 807 samples, but not in the baseline sample, should be reported as having developed during 808 therapy. In addition, baseline samples should be analyzed to identify HCV genetic 809 polymorphisms that are associated with differential antiviral activity with the new agent. 810 811 Viral resistance-associated polymorphisms or substitutions observed in clinical trials but 812 not identified and characterized in nonclinical virology experiments should be evaluated 813 phenotypically by introducing the changes into the HCV genome, and determining the 814 conferred fold-shift in susceptibility to the agent using appropriate cell culture and/or 815 biochemical assays. In addition, phenotypic analyses should be performed using baseline 816 and on-treatment clinical isolates from a subset of trial patients representative of the HCV 817 genetic diversity and virologic responses observed in clinical trials. 818
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819 Emerging data with new DAAs suggest resistance-associated substitutions may persist 820 for long periods of time in the absence of drug selection. Because DAAs within the same 821 drug class typically have overlapping resistance profiles, the persistence of resistance822 associated substitutions can significantly limit a patient’s future treatment options. 823 Therefore, patients who have detectable resistance-associated substitutions at treatment 824 cessation or follow-up should be followed for an extended period, preferably at least 1 825 year after treatment cessation, to assess the persistence of resistance-associated 826 substitutions. The potential persistence of resistance-associated substitutions should be 827 characterized for patients enrolled in phase 1 and phase 2 clinical trials so that 828 preliminary long-term follow-up data are obtained by the time of completion of phase 3 829 trials. Genotyping methodology should be capable of assessing the quantity of resistant 830 viruses during the outgrowth of wild-type virus. 831 832 Sponsors should consider genotyping regions outside the direct HCV genome target 833 depending on the characteristics of the antiviral agent and interactions of the target with 834 other viral proteins. In cases when resistance is suspected based on viral RNA kinetics, 835 but genotypic evidence of resistance is not detected, sponsors should also consider 836 performing additional genotypic analyses using a method sufficiently sensitive to detect 837 minority variants.16 838 839 2. PK/PD Considerations 840 841 Trials conducted in HCV-infected patients should include assessment of 842 pharmacokinetics and the relationship between exposure and virologic success and 843 toxicity in all patients. 844 845 Sponsors can use a combination of dense and sparse sampling throughout development to 846 characterize the pharmacokinetics of the investigational agent. For example, a dense 847 sampling schedule should be implemented in monotherapy trials. In longer term trials, 848 however, a dense sampling schedule might not be feasible. Alternatively, sparse 849 sampling from these trials can be combined with dense PK data from earlier trials for 850 analysis. Sparse PK samples should be obtained at the time of key virologic assessments, 851 such as weeks 4, 12, 24, and 48. These data can then be subjected to appropriate 852 population PK analysis.17 PK samples for evaluation of Peg-Interferon/RBV or any other 853 agent in the regimen should also be collected in trials of combination therapy to assist in 854 exposure-response analyses. 855 856 Sponsors can use the following two broad approaches to characterize the relationship 857 between exposure and viral kinetics or virologic success of the investigational agent, 858 depending on the stage of development and purpose of the analysis. Both approaches
16 Additional guidance for reporting HCV drug resistance can be found in the guidance for industry
Antiviral Product Development — Conducting and Submitting Virology Studies to the Agency: Guidance for Submitting HCV Resistance Data.
17 See the guidance for industry Population Pharmacokinetics.
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859 allow for exploration of relevant covariates. These analyses should also account for the 860 development of resistance to the investigational agent. 861 862 (1) To aid the design of phase 2b or phase 3 trials, with respect to dose and regimen 863 choice, a mechanistic approach relating drug concentrations and viral kinetics is 864 most appropriate. Specifically, sponsors should develop a viral kinetic model that 865 describes time-dependent changes in HCV infection during treatment, includes a 866 mechanistically appropriate targeted drug effect, and, includes components to 867 describe virologic breakthrough, relapse, and long-term viral response. 868 869 (2) When sufficient SVR12 or SVR24 data are available, a simplified analysis 870 relating proportion of patients with virologic success and appropriate exposure 871 variable (e.g., Cmin or area under curve) can be used to support evidence of 872 effectiveness and justify dose selection.18 873 874 3. Special Populations 875 876 Treatments for patients with hepatic impairment or pre- or post-transplant patients, 877 patients co-infected with HIV and HCV, and patients with decompensated cirrhosis are 878 unmet medical needs. We strongly encourage sponsors to discuss early in development 879 the process to determine appropriate timing for initiating trials in these populations. 880 881 a. Hepatic impairment 882 883 A hepatic impairment trial to inform the need for dose modifications should be conducted 884 early in development so that patients with hepatic impairment can be included in phase 2 885 and 3 trials, as appropriate. These data also can support use in pre- or post-transplant 886 patients. 887 888 b. HIV/HCV co-infected patients 889 890 It is estimated that nearly 30 percent of patients with HIV are co-infected with HCV 891 (Sulkowski 2008). Patients with HIV/HCV co-infection are at higher risk of more rapid 892 progression of liver disease than patients with HCV infection alone. In addition, 893 treatment responses (SVR24) with SOC in co-infection are generally less than responses 894 (SVR24) with HCV infection alone. 895 896 As needed, and based on a particular investigational drug’s metabolic profile, drug-drug 897 interaction trials should be conducted before trials in co-infected patients to support 898 concomitant dosing of a new HCV drug and antiretroviral drugs. 899 900 We strongly suggest that an initial NDA for the treatment of HCV contain some clinical 901 data on the HIV/HCV co-infected population at time of filing, including:
18 See the guidance for industry Exposure-Response Relationships — Study Design, Data Analysis, and Regulatory Applications.
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902 903 • Drug-drug interaction data with the most commonly used HIV drugs 904 905 • Safety data on a cohort of co-infected patients receiving the drug for the 906 recommended treatment duration 907 908 • Preliminary efficacy data characterizing, at minimum, on-treatment responses 909 910 With the above-mentioned preliminary data, labeling describing drug interactions and 911 preliminary safety data may be appropriate. For more extensive labeling that expands the 912 indication to the HIV co-infected population or includes a description of efficacy in the 913 co-infected population, a clinical trial demonstrating efficacy and safety in at least 300 914 co-infected patients may be appropriate. In some cases, single-arm prospective trials 915 (with historical controls) may be appropriate for the co-infected population if trials in the 916 HCV mono-infected population showed robust and substantial efficacy of the new DAA 917 added to SOC. Trials in co-infected patients should evaluate SVR at 24 weeks after end 918 of therapy as the primary efficacy endpoint. As part of the safety evaluation, loss of HIV 919 efficacy (rebounds in HIV viral RNA) should be assessed. 920 921 c. Patients with decompensated cirrhosis 922 923 SOC, interferon-based regimens are not considered appropriate for patients with 924 decompensated cirrhosis or for most patients pre- or post-liver transplant; therefore, 925 treatment with multiple investigational DAAs is likely to be needed to achieve viral 926 suppression. Because there are currently no HCV treatments in patients with 927 decompensated cirrhosis and because spontaneous resolution of HCV infection in this 928 population is consistently negligible, dose-response trials or historically controlled 929 efficacy and safety trials showing clinically significant SVRs may be appropriate to 930 expand the labeling for this population. However, as more drugs become available for 931 study in combination regimens, we will encourage comparative trials. SVR24 should be 932 the primary efficacy endpoint, but other important endpoints include progression of liver 933 disease, transplantation, and mortality. SVR24 is an important endpoint notwithstanding 934 disease progression requiring transplantation, because SVR24 will likely translate into 935 prevention of infection of a newly transplanted liver. 936 937 The contribution of each agent toward overall efficacy of a regimen should be 938 demonstrated, but can be based on data such as that discussed in section III.B.6, 939 Statistical Considerations. For example, trials showing the efficacy of one new DAA 940 added to Peg-Interferon/RBV in patients with compensated cirrhosis can serve as 941 supportive data for demonstrating contribution toward efficacy in other populations that 942 are more difficult to study. 943 944 Plans for expanded access trials or safety trials should also be considered for this 945 population early in development. 946
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947 d. Pediatric populations 948 949 Early trials of DAAs should enroll adult patients only, reserving pediatric exposure until 950 the pharmacokinetics, pharmacodynamics, and safety of the agent are reasonably well951 defined. Sponsors are encouraged to begin discussions of their pediatric formulation and 952 clinical development plan early in development, but pediatric clinical trials should be 953 initiated once phase 2 adult data characterizing the safety profile and initial antiviral 954 efficacy are available. If clinical trials in adults have demonstrated no safety concern 955 specific to a histologic stage, liver biopsies are not recommended for routine entry criteria 956 into pediatric trials. If biopsies are done because they are clinically indicated, biopsy data 957 should be provided. 958 959 4. Early Access/Treatment INDs 960 961 Some hepatitis C-infected patients who have not responded to approved treatments and/or 962 who are at substantial risk of liver disease progression may benefit from access to new 963 therapeutic options before their approval. Treatment INDs or other access protocols for 964 DAAs may be appropriate when sufficient clinical trial data have been generated to 965 characterize a reasonably safe and active dose of an investigational agent. Ideally, the 966 timing of a treatment IND would occur after phase 3 trials were fully enrolled or well 967 underway so as not to interfere with phase 3 drug development. Treatment INDs can 968 provide early access while phase 3 trials are being completed, analyzed, submitted, and 969 reviewed by the FDA. Alternatively, individual patient INDs and treatment access 970 protocols for intermediate size populations may be possible. In contrast to treatment 971 INDs for larger populations during or after phase 3 trials, access for intermediate size 972 populations (approximately 100 patients or fewer), can occur earlier in drug 973 development. 974 975 Historically, early access programs with HIV allowed many people to gain access to life976 saving drugs. However, for some individuals, early access to a drug resulted in what 977 amounted to sequential monotherapy and the emergence of multidrug resistance. 978 Because treatment of CHC requires multiple agents to achieve SVR and to reduce the 979 emergence of drug resistance to single agents or drug classes, treatment INDs that include 980 two or more investigational agents or that allow co-enrollment in several treatment IND 981 programs simultaneously are desirable, particularly for previous null responders or for 982 patients who cannot take interferon-based regimens. However, treatment use of multiple 983 investigational agents should be supported by: 984 985 • Data and rationale that characterize the potential for PK drug interactions and 986 potential for overlapping toxicity. Data to support dose modifications if drug 987 interactions are present. 988 989 • Information suggesting the potential for additive or synergistic activity and no or 990 minimal overlapping resistance profiles. 991
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992 Refer to section III.A.4.d., Combination therapy with multiple DAAs, for the data needed 993 to support treatment use of multiple investigational agents. 994
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995 GLOSSARY OF ACRONYMS 996 997 CHC chronic hepatitis C 998 DAA direct-acting antiviral agent 999 HCC hepatocellular carcinoma 1000 HCV hepatitis C virus 1001 HCV RNA hepatitis C virus ribonucleic acid 1002 HIV human immunodeficiency virus 1003 IFN interferon 1004 IL interleukin 1005 Peg pegylated 1006 RBV ribavirin 1007 RVR rapid virologic response 1008 SOC standard of care 1009 SVR sustained virologic response 1010 SVR24 sustained virologic response 24 weeks after stopping treatment 1011
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1012 REFERENCES 1013 1014 Arase, Y, K Ikeda, F Suzuki, Y Suzuki, S Saitoh, M Kobayashi, N Akuta, T Someya, R 1015 Koyama, T Hosaka, H Sezaki, M Kobayashi, H Kumada, 2007, Long-Term Outcome 1016 After Interferon Therapy in Elderly Patients With Chronic Hepatitis C, Intervirology, 1017 50(1):16-23. 1018 1019 Braks, RE, N Ganne-Carrie, H Fontaine, J Paries, V Grando-Lemaire, M Beaugrand, S 1020 Pol, JC Trinchet, 2007, Effect of Sustained Virological Response on Long-Term 1021 Clinical Outcome in 113 Patients With Compensated Hepatitis C-Related Cirrhosis 1022 Treated By Interferon Alpha and Ribavirin, World J Gastroenterol, Nov 14, 1023 13(42):5648-53. 1024 1025 Bruno, S, T Stroffolini, M Colombo, S Bollani, L Benvegnù, G Mazzella, A Ascione, T 1026 Santantonio, F Piccinino, P Andreone, A Mangia, GB Gaeta, M Persico, S Fagiuoli, 1027 PL Almasio; Italian Association of the Study of the Liver Disease (AISF), 2007, 1028 Sustained Virological Response to Interferon-Alpha Is Associated With Improved 1029 Outcome in HCV-Related Cirrhosis: A Retrospective Study, Hepatology, Mar, 1030 45(3):579-87. 1031 1032 Gane, EJ, 2008, The Natural History of Recurrent Hepatitis C and What Influences This, 1033 Liver Transpl., Suppl2: S36-44. 1034 1035 Ge, D, J Fellay, AJ Thompson, JS Simon, KV Shianna, TJ Urban, EL Heinzen, P Qiu, 1036 AH Bertelsen, AJ Muir, M Sulkowski, JG McHutchison, DB Goldstein, 2009, Genetic 1037 Variation in IL-28B Predicts Hepatitis C Treatment-Induced Viral Clearance, Nature, 1038 461:399-401. 1039 1040 Ghany, MG, DB Strader, DL Thomas, LB Seeff, 2009, Diagnosis, Management, and 1041 Treatment of Hepatitis C: An Update, Hepatology, 49:1335-1374. 1042 1043 Imai, Y, S Kawata, S Tamura, I Yabuuchi, S Noda, M Inada, Y Maeda, Y Shirai, T 1044 Fukuzaki, I Kaji, H Ishikawa, Y Matsuda, M Nishikawa, K Seki, Y Matsuzawa, 1998, 1045 Relation of Interferon Therapy and Hepatocellular Carcinoma in Patients With 1046 Chronic Hepatitis C, Osaka Hepatocellular Carcinoma Prevention Study Group, Ann 1047 Intern Med, Jul 15, 129(2):94-9, PMID: 9669992. 1048 1049 Kim, WR, 2002, The Burden of Hepatitis C in the United States, Hepatology, 1050 36(Suppl):S30-S34. 1051 1052 Manos, MM, WK Zhao, VA Shvachko, N Volkova, CP Quesenberry, Viral Hepatitis 1053 Registry, Kaiser Permanente Division of Research, Oakland, CA, 2009, Long Term 1054 Outcomes in Patients Treated With Peg-Interferon/Ribavirin Therapy for Hepatitis C: 1055 The Substantial Effect of Sustained Viral Response (SVR) on Liver Disease, Mortality 1056 and Diabetes, 13th International Symposium on Viral Hepatitis and Liver Disease, 1057 Abstract PL-3.
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1058 Neumann, AU, NP Lam, H Dahari, DR Gretch, TE Wiley, TJ Layden, AS Perelson, 1059 1998, Hepatitis C Viral Dynamics In Vivo and the Antiviral Efficacy of Interferon1060 alpha Therapy, Science, Oct 2, 282(5386):103-7. 1061 1062 Okanoue, T, Y Itoh, M Minami, S Sakamoto, K Yasui, M Sakamoto, K Nishioji, Y 1063 Murakami, K Kashima, 1999, Interferon Therapy Lowers the Rate of Progression to 1064 Hepatocellular Carcinoma in Chronic Hepatitis C but not Significantly in an Advanced 1065 Stage: A Retrospective Study in 1148 Patients, Viral Hepatitis Therapy Study Group, 1066 J Hepatol, Apr, 30(4):653-9, PMID: 10207807. 1067 1068 Perelson, AS, 2009, HCV Kinetics, 13th International Symposium on Viral Hepatitis and 1069 Liver Disease, Washington, DC. 1070 1071 Shiratori, Y, Y Ito, O Yokosuka, F Imazeki, R Nakata, N Tanaka, Y Arakawa, E 1072 Hashimoto, K Hirota, H Yoshida, Y Ohashi, M Omata; Tokyo-Chiba Hepatitis 1073 Research Group, 2005, Antiviral Therapy for Cirrhotic Hepatitis C: Association With 1074 Reduced Hepatocellular Carcinoma Development and Improved Survival, Ann Intern 1075 Med, Jan 18, 142(2):105-14, PMID: 15657158. 1076 1077 Sulkowski, MS, 2008, Viral Hepatitis and HIV Coinfection, J Hepatol, Feb, 48(2):3531078 67. 1079 1080 Veldt, BJ, EJ Heathcote, H Wedemeyer, J Reichen, WP Hofmann, S Zeuzem, MP 1081 Manns, BE Hansen, SW Schalm, HL Janssen, 2007, Sustained Virologic Response 1082 and Clinical Outcomes in Patients With Chronic Hepatitis C and Advanced Fibrosis, 1083 Ann Intern Med, 147:677-684. 1084 1085 Yoshida, H, Y Arakawa, M Sata, S Nishiguchi, M Yano, S Fujiyama, G Yamada, O 1086 Yokosuka, Y Shiratori, M Omata, 2002, Interferon Therapy Prolonged Life 1087 Expectancy Among Chronic Hepatitis C Patients, Gastroenterology, Aug, 123(2):4831088 91. 1089 1090 Yoshida, H, Y Shiratori, M Moriyama, et al., 1999, Interferon Therapy Reduces the Risk 1091 for Hepatocellular Carcinoma: National Surveillance Program of Cirrhotic and 1092 Noncirrhotic Patients With Chronic Hepatitis C in Japan, IHIT Study Group, 1093 Inhibition of Hepatocarcinogenesis by Interferon Therapy, Ann Intern Med, Aug 3, 1094 131(3):174-81. 1095
27
Chronic Hepatitis C Virus
Infection: Developing Direct-
Acting Antiviral Agents for
Treatment
DRAFT GUIDANCE
This guidance document is being distributed for comment purposes only.
Comments and suggestions regarding this draft document should be submitted within 60 days of publication in the Federal Register of the notice announcing the availability of the draft guidance. Submit comments to the Division of Dockets Management (HFA-305), Food and Drug Administration, 5630 Fishers Lane, rm. 1061, Rockville, MD 20852. All comments should be identified with the docket number listed in the notice of availability that publishes in the Federal Register.
For questions regarding this draft document contact Jeffrey Murray at (301) 796-1500.
U.S. Department of Health and Human Services
Food and Drug Administration
Center for Drug Evaluation and Research (CDER)
September 2010
Clinical Antimicrobial
I:\9216dft.doc
08/31/10
Guidance for Industry
Chronic Hepatitis C Virus
Infection: Developing Direct-
Acting Antiviral Agents for
Treatment
Additional copies are available from:
Office of Communications, Division of Drug Information
Center for Drug Evaluation and Research
Food and Drug Administration
10903 New Hampshire Ave., Bldg. 51, rm. 2201
Silver Spring, MD 20993-0002
Tel: 301-796-3400; Fax: 301-847-8714; E-mail: druginfo@fda.hhs.gov
http://www.fda.gov/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/default.htm
U.S. Department of Health and Human Services
Food and Drug Administration
Center for Drug Evaluation and Research (CDER)
September 2010
Clinical Antimicrobial
TABLE OF CONTENTS
I.
INTRODUCTION
.............................................................................................................
1
II.
BACKGROUND
...............................................................................................................
2
III.
DEVELOPMENT PROGRAM
.......................................................................................
4
A.
General Considerations
.................................................................................................................
4
1.
Pharmacology/Toxicology Development Considerations
................................................................
4
2.
Nonclinical Virology Development Considerations
.........................................................................
5
a.
Mechanism of action
.................................................................................................................
5
b. Antiviral activity in cell culture
................................................................................................
5
c.
Resistance and cross-resistance
.................................................................................................
6
d. Combination antiviral activity
..................................................................................................
6
e.
Activity in animal models
.........................................................................................................
6
3.
Drug Development Population
.........................................................................................................
7
4.
Early Phase Clinical Development Considerations
.........................................................................
7
a.
First-in-human trials
..................................................................................................................
7
b. Phase 1b (proof-of-concept) trials
.............................................................................................
8
c.
Phase 2 trials and dose-finding
..................................................................................................
8
d. Combination therapy with multiple DAAs
.............................................................................
10
e.
Other phase 2 trial design considerations
................................................................................
11
5.
Efficacy Considerations
.................................................................................................................
11
6.
Safety Considerations
.....................................................................................................................
12
B.
Specific Efficacy Trial Design Considerations
...........................................................................
13
1.
Trial Design
...................................................................................................................................
13
2.
Trial Population
.............................................................................................................................
14
a.
Patient enrollment definition
...................................................................................................
14
b. Patient enrollment biopsy considerations
................................................................................
15
3.
Randomization, Stratification, and Blinding
..................................................................................
15
4.
Efficacy Endpoints
..........................................................................................................................
16
5.
Trial Procedures and Timing of Assessments
................................................................................
16
6.
Statistical Considerations
...............................................................................................................
16
a.
Analysis populations
...............................................................................................................
16
b. Efficacy analyses
.....................................................................................................................
16
c.
Handling of missing data
.........................................................................................................
17
d. Interim analyses and data monitoring committees
..................................................................
18
e.
Statistical analysis plan
...........................................................................................................
19
C.
Other Considerations
...................................................................................................................
19
1.
Clinical Virology Considerations
...................................................................................................
19
2.
PK/PD Considerations
...................................................................................................................
20
3.
Special Populations
........................................................................................................................
21
a.
Hepatic impairment
.................................................................................................................
21
b. HIV/HCV co-infected patients
................................................................................................
21
c.
Patients with decompensated cirrhosis
....................................................................................
22
d. Pediatric populations
...............................................................................................................
23
4.
Early Access/Treatment INDs
........................................................................................................
23
GLOSSARY OF ACRONYMS
.................................................................................................
25
REFERENCES
............................................................................................................................
26
Contains Nonbinding Recommendations
Draft — Not for Implementation
1 Guidance for Industry1
2 Chronic Hepatitis C Virus Infection: Developing Direct3 Acting Antiviral Agents for Treatment
4
5
6
7
8
This draft guidance, when finalized, will represent the Food and Drug Administration’s (FDA’s) 9
current thinking on this topic. It does not create or confer any rights for or on any person and 10
does not operate to bind FDA or the public. You can use an alternative approach if the approach 11
satisfies the requirements of the applicable statutes and regulations. If you want to discuss an 12
alternative approach, contact the FDA staff responsible for implementing this guidance. If you 13
cannot identify the appropriate FDA staff, call the appropriate number listed on the title page of 14
this guidance. 15
16 17 18 19 I. INTRODUCTION 20 21 This guidance provides recommendations for the development of direct-acting antiviral 22 agents (DAAs) regulated within the Center for Drug Evaluation and Research at the Food 23 and Drug Administration (FDA) for the treatment of chronic hepatitis C (CHC) infection. 24 For the purpose of this guidance, we define direct-acting hepatitis C virus (HCV) 25 antivirals as agents that interfere with specific steps in the HCV replication cycle through 26 a direct interaction with the HCV polyprotein and its cleavage products. This guidance is 27 intended to serve as a focus for continued discussions among the review divisions, 28 pharmaceutical sponsors, the academic community, and the public.2 The organization of 29 the guidance parallels the development plan for a particular drug or biologic.3 30 31 This guidance does not address the development of immune-based agents for the 32 treatment of HCV infection such as new interferon products. Therapeutics without 33 antiviral mechanisms intended to mitigate or reverse clinical or pathophysiological 34 outcomes of CHC, such as prevention of hepatocellular carcinoma (HCC), reversal of 35 fibrosis, or treatment of acute hepatitis C, are not addressed in this guidance. 36
1 This guidance has been prepared by the Division of Antiviral Products in the Center for Drug Evaluation and Research (CDER) at the Food and Drug Administration.
2 In addition to consulting guidance documents, sponsors are encouraged to contact the division to discuss specific issues that arise during the development of DAAs.
3 For the purposes of this guidance, all references to drugs include both human drugs and therapeutic biological products unless otherwise specified.
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37 Additionally, general issues of clinical trial design or statistical analyses for HCV trials 38 are not addressed in this guidance. Those topics are addressed in the ICH guidances for 39 industry E9 Statistical Principles for Clinical Trials and E10 Choice of Control Group 40 and Related Issues in Clinical Trials.4 This guidance also does not contain details 41 regarding nonclinical safety and toxicology studies. Such studies for direct-acting HCV 42 antivirals generally should be conducted in standard animal models as described in the 43 guidance for industry Nonclinical Safety Evaluation of Drug or Biologic Combinations. 44 45 FDA’s guidance documents, including this guidance, do not establish legally enforceable 46 responsibilities. Instead, guidances describe the Agency’s current thinking on a topic and 47 should be viewed only as recommendations, unless specific regulatory or statutory 48 requirements are cited. The use of the word should in Agency guidances means that 49 something is suggested or recommended, but not required. 50 51 52 II. BACKGROUND 53 54 HCV is a small positive-strand RNA virus in the Flaviviridae family. Six viral 55 genotypes, numbered 1 to 6, have been identified; some have been divided into multiple 56 subtypes (e.g., genotype 1 subtypes 1a and 1b). In the United States, genotype 1 is the 57 most common (70 to 90 percent), followed by genotypes 2 and 3. Other genotypes occur 58 uncommonly in the United States, but may predominate in other parts of the world. 59 60 In the United States, HCV infection causes 20 percent of all cases of acute viral hepatitis 61 and 70 to 90 percent of all cases of HCC. Estimates show nearly 3.2 million Americans 62 are chronically infected with HCV. CHC is currently the leading indication in the United 63 States for liver transplantation, and predictive modeling suggests that without effective 64 treatment interventions significant increases in CHC-associated liver morbidity, 65 mortality, and health care costs are likely (Kim 2002). 66 67 Current treatment of CHC typically is a pegylated interferon administered in combination 68 with ribavirin (Peg-Interferon/RBV), often referred to in hepatitis C clinical trials as 69 standard of care (SOC). The goal of treatment is sustained virologic response (SVR), 70 defined as undetectable plasma HCV RNA at week 24 following treatment cessation 71 (SVR24). Total duration of current treatment depends on genotype, with longer 72 treatment durations needed to achieve SVR for genotypes 1 and 4 and shorter treatment 73 durations needed for genotypes 2 and 3. SVR rates in treatment-naive patients receiving 74 Peg-Interferon/RBV typically are in the range of 40 percent to 45 percent for viral 75 genotype 1 and are 70 percent to 80 percent for genotypes 2 and 3 (Ghany, Stradler, et al.
4 We update guidances periodically. To make sure you have the most recent version of a guidance, check the FDA Drugs guidance Web page at http://www.fda.gov/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/default.htm.
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76 2009).5 SVR rates for blacks and HIV co-infected patients with genotype 1 HCV are in 77 the range of 20 percent to 30 percent (in some studies less than 20 percent), which is 78 substantially lower than rates for whites and patients who are not co-infected. 79 80 On-treatment virologic measurements at early time points can predict the likelihood of 81 SVR and are often used to guide treatment duration. When treating with interferon-based 82 regimens, health care providers generally stop treatment if patients do not have at least a 83 2 log10 drop from baseline in HCV RNA at week 12 or do not have an undetectable HCV 84 RNA by week 24, because not meeting these interim virologic response criteria results in 85 a low likelihood of SVR. Three terms relating to on-treatment responses used in clinical 86 trials include: (1) rapid virologic response (RVR), meaning an undetectable HCV RNA 87 at 4 weeks of treatment; (2) complete early virologic response, meaning an undetectable 88 HCV RNA at week 12 of treatment; and (3) extended RVR, meaning an undetectable 89 HCV RNA at week 4 that persists through week 12. These measurements are sometimes 90 used to guide treatment duration strategies in clinical trials. 91 92 Even among patients who achieve SVR, liver injury may persist and hepatic 93 complications may occur; although the likelihood of hepatic complications appears to be 94 substantially reduced compared to patients who do not achieve SVR. Multiple 95 observational cohorts show correlations between SVR and improvements in clinical 96 outcomes of interest, such as development of HCC, hepatic events, fibrosis, and all-cause 97 mortality (Yoshida, Shiratori, et al. 1999; Yoshida, Arakawa, et al. 2002; Shiratori, Ito, et 98 al. 2005; Okanoue, Itoh, et al. 1999; Imai, Kawata, et al. 1998; Arase, Ikeda, et al. 2007; 99 Veldt, Heathcote, et al. 2007, Braks, Ganne-Carrie, et al. 2007; Bruno, Stroffolini, et al. 100 2007; Manos, Zhao, et al. 2009). Evaluating clinical outcomes from prospective, 101 randomized controlled clinical trials is challenging because of the difficulty of 102 maintaining patients on a randomized arm without intervening therapy for a sufficient 103 duration (many years) to identify late-occurring clinical events such as HCC. 104 105 Pegylated interferons and RBV are difficult to tolerate and have significant adverse event 106 profiles that limit treatment in many patients or result in substantial morbidity. 107 Therefore, new drugs are needed that increase SVR rates when added to current therapy, 108 that shorten the duration of interferon-based regimens, or that replace components of 109 current therapy in patients who cannot tolerate interferon or RBV. New drugs are also 110 needed to construct regimens in patients with decompensated cirrhosis and in patients 111 undergoing liver transplant. 112 113 Host factors, such as genetic polymorphisms, metabolic parameters, and viral factors 114 (i.e., genomic mutations), are being investigated for their roles in predicting response to 115 treatments for CHC. Recently, a genetic polymorphism near the IL-28B gene, encoding 116 interferon-l-3 (IFN-l-3), has been shown in several studies to predict an approximately 117 two-fold change in response to interferon-based treatment regimens in patients of
5 See also labeling information for PegIntron and Pegasys at http://www.accessdata.fda.gov/scripts/cder/drugsatfda/index.cfm?CFID=42688251&CFTOKEN=cea143f9 dc49c115-37E6D01E-0AF3-6971-CCAA04EECE6DE6A7.
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118 African-American and European ancestries (Ge, Fellay, et al. 2009). At least one test for 119 the IL-28B polymorphism is now available to physicians and for use in clinical protocols. 120 121 122 III. DEVELOPMENT PROGRAM 123 124 A. General Considerations 125 126 1. Pharmacology/Toxicology Development Considerations 127 128 Pharmacology/toxicology development for single direct-acting HCV antivirals should 129 follow existing guidances for drug development.6 130 131 Guidance suggests conducting nonclinical combination studies to support clinical trials 132 for combination drugs.7 However, similar to the approach used for HIV and oncology 133 drugs, we do not recommend that these nonclinical studies be conducted routinely for the 134 following reasons: 135 136 • In clinical practice, DAAs are likely to be used with multiple hepatitis C drugs, 137 including interferon and RBV and other DAAs, in multiple different 138 combinations; it would not be feasible to conduct animal studies for all potentially 139 relevant combinations 140 141 • Given the difficulty of conducting combination toxicologic studies that may 142 require multiple different drugs and multiple dose combinations, we believe that 143 nonclinical studies would be more interpretable and may offer more useful data 144 by looking at individual agents at multiple and higher doses 145 146 • Single- and multiple-dose drug-interaction trials in humans and in vitro metabolic 147 studies can screen for potential pharmacokinetic (PK) drug interactions that may 148 lead to safety issues 149 150 To support clinical trials evaluating 2 or more investigational DAAs for up to 90 days, we 151 recommend a minimum of 3 months repeat-dose nonclinical toxicity studies in a rodent 152 and nonrodent species for each individual agent. Longer term data on individual agents 153 (6-month rodent, 9-month nonrodent) can support longer duration combination clinical 154 trials, depending on the toxicity profile (see ICH M3(R2)). 155 156 Nonclinical combination studies of an investigational antiviral plus approved SOC (e.g., 157 Peg-Interferon/RBV) may not be needed unless data from nonclinical studies of an
6 See the ICH guidances for industry M3(R2) Nonclinical Safety Studies for the Conduct of Human Clinical Trials and Marketing Authorization for Pharmaceuticals and S6 Preclinical Safety Evaluation of Biotechnology-Derived Pharmaceuticals.
7 See the guidance for industry Nonclinical Safety Evaluation of Drug or Biologic Combinations.
4
Contains Nonbinding Recommendations
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158 investigational antiviral drug suggest a potential for increased or synergistic toxicity with 159 the approved therapeutic agents. 160 161 2. Nonclinical Virology Development Considerations 162 163 DAAs for the treatment of CHC should be tested in cell culture for antiviral activity 164 before submission of an initial investigational new drug application (IND). Information 165 about pre-investigational new drug testing and information regarding appropriate 166 nonclinical assays is available from the FDA.8 Additional recommendations for general 167 antiviral drug development can be found in the guidance for industry Antiviral Product 168 Development — Conducting and Submitting Virology Studies to the Agency. 169 170 a. Mechanism of action 171 172 The mechanism by which a DAA exhibits anti-HCV activity should be investigated in 173 studies that include evaluation of the effect of the agent on relevant stages of the virus life 174 cycle. Mechanism of action investigations should include appropriate controls for 175 assessing the specificity of anti-HCV activity, which may include assessments of activity 176 against HCV proteins that are not targeted by the candidate agent, relevant host proteins, 177 or other viruses. 178 179 b. Antiviral activity in cell culture 180 181 The antiviral activity of a new agent should be characterized in cell culture to identify a 182 target plasma concentration for evaluation in HCV-infected patients. Antiviral activity of 183 candidate agents targeting nonstructural components should be assessed using HCV 184 genotype 1a- and 1b-derived replicon systems, and a 50 percent effective concentration 185 (EC50) determined. Nonclinical studies should include assessments of antiviral activity 186 against the major HCV genotypes and subtypes. Assessments of antiviral activity against 187 replication models using HCV components derived from multiple clinical isolates are 188 also recommended, because antiviral activity can vary for strains within each subtype. If 189 differences in susceptibility are observed for different clinical isolates within the same 190 viral genotype or subtype, additional genotypic and phenotypic characterizations should 191 be conducted to identify genetic polymorphisms that may affect HCV susceptibility to the 192 new agent. 193 194 The antiviral activity of agents that target HCV entry functions can be evaluated using 195 HCV pseudoparticle systems. Assessments of antiviral activity against HCV grown in 196 cell culture are recommended for any anti-HCV agent when appropriate. The cytotoxic 197 effects of the agent should be quantified directly in the cells used for assessing anti-HCV 198 activity, and a 50 percent cytotoxic concentration (CC50) and a therapeutic index should 199 be calculated. Cytotoxicity should also be assessed using various cell lines and primary 200 cells cultured under proliferating and nonproliferating conditions. Sequestration of the
8 See the FDA Web site http://www.fda.gov/Drugs/DevelopmentApprovalProcess/HowDrugsareDevelopedandApproved/Approval Applications/InvestigationalNewDrugINDApplication/Overview/ucm077546.htm.
5
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201 agent by serum proteins should also be assessed and a serum-adjusted EC50 value 202 determined. We recommend evaluation of the agent’s antiviral activity at different 203 concentrations of human serum and extrapolation to a 100 percent human serum EC50 204 value. 205 206 c. Resistance and cross-resistance 207 208 The ability of HCV to develop resistance to a DAA when subjected to drug pressure 209 should be examined in appropriate cell culture models. Amino acid or nucleotide 210 substitutions associated with the development of resistance to the candidate agent should 211 be determined and validated by introducing the changes into the HCV genome and 212 determining the conferred fold-shift in susceptibility using appropriate cell culture and/or 213 biochemical assays. Results from these studies should be used to: (1) determine whether 214 the genetic barrier for resistance development is high or low; (2) predict whether the 215 genetic barrier for resistance may vary as a function of concentration of the new agent; 216 (3) reveal potential resistance pathways and the potential for cross-resistance with other 217 anti-HCV agents; and (4) support the agent’s hypothesized mechanism of action. 218 219 Resistance studies should include evaluation of the potential for cross-resistance, both to 220 approved agents and to agents in development, particularly focusing on those in the same 221 drug class. Although the mechanism of action for RBV remains unclear, RBV should be 222 included in assessments of cross-resistance for inhibitors that target the NS5B RNA223 dependent RNA polymerase. 224 225 d. Combination antiviral activity 226 227 Most, if not all, DAAs for HCV will be used to treat CHC in combination with other 228 approved drugs. Early in development, cell culture combination antiviral activity 229 relationships of the new agent and pegylated interferons and the new agent and RBV 230 should be characterized to determine whether the combination antiviral activity is 231 additive, synergistic, or antagonistic. Additional combination antiviral activity studies 232 with other candidate anti-HCV agents should be conducted if future combination therapy 233 with other agents is anticipated. For all combination antiviral activity assessments, 234 sponsors should provide combination index values when the two agents are combined at 235 or near their individual EC50 values, and studies should include controls for cytotoxicity. 236 Combination antiviral activity relationships for HIV and HCV agents with similar 237 mechanisms of action (e.g., nucleoside analogue polymerase/reverse-transcriptase 238 inhibitors, protease inhibitors) should also be assessed before testing combinations of the 239 agents in HIV/HCV co-infected patients. 240 241 e. Activity in animal models 242 243 Demonstration of anti-HCV activity in an animal model is not needed. However, if such 244 studies are conducted and provided in support of an anti-HCV therapy program, reported 245 data should include the HCV genotype/subtype used, time course plots of viral load data
6
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246 for each animal, and an assessment of resistance development that includes monitoring 247 the persistence of resistant virus in the absence of anti-HCV treatment. 248 249 3. Drug Development Population 250 251 Overall drug development programs should include a broad population as appropriate for 252 the characteristics of the antiviral agent. However, a DAA may have differential activity 253 against different HCV genotypes or subtypes; therefore, development can be targeted to a 254 specific genotype (e.g., genotype 1 versus genotype 2 or 3). We recommend including 255 patients diagnosed with compensated cirrhosis in phase 2 and phase 3 trials. Also, we 256 encourage the study of combinations of direct-acting HCV antivirals in patients with the 257 greatest need for new agents, such as patients who cannot tolerate interferon, patients for 258 whom interferon is contraindicated, transplant patients, and patients with decompensated 259 cirrhosis. DAAs can be studied in combination with other DAAs and with or without 260 SOC in HIV co-infected patients as soon as appropriate based on the availability of data. 261 Trials in the above-mentioned subgroups may need to be supported by preliminary data 262 from trials to define safety and pharmacokinetics, such as hepatic impairment trials and 263 drug-drug interaction trials (e.g., antiretrovirals for HIV, immunosuppresants for 264 transplant). 265 266 CHC is a disease that is present worldwide and clinical trials typically are conducted 267 internationally. However, trials should include adequate U.S. patient representation to 268 ensure applicability of trial results to the U.S. population. An adequate representation of 269 males and females, races, ages, and weights is recommended during drug development, 270 especially in phase 3 trials. Because race (e.g., black, Asian) and ethnicity (e.g., Latino) 271 affect response rates to interferon-based regimens, it is important to ensure that there is 272 sufficient diversity in clinical trial demographics to conduct meaningful analyses of such 273 groups. Furthermore, in addition to viral genotypes, host genotypes are emerging as 274 correlates of clinical response to antivirals and may partially explain differences in 275 response rates by race; therefore, collection of patient DNA is an important 276 consideration.9 277 278 4. Early Phase Clinical Development Considerations 279 280 The early clinical evaluation of new DAAs should follow a rational plan to provide 281 sufficient data to establish preliminary safety and activity to support phase 3 trials. 282 283 a. First-in-human trials 284 285 In general, we recommend single- and/or multiple-ascending-dose trials in healthy adult 286 subjects to assess safety and pharmacokinetics for the first-in-human trials. However, 287 single-dose and short multiple-dose PK trials (see below) can also be conducted in HCV288 infected patients, particularly if nonclinical data suggest a drug may be genotoxic or 289 otherwise unacceptable for studies in healthy volunteers.
9 See the guidance for industry Pharmacogenomic Data Submissions.
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290 291 b. Phase 1b (proof-of-concept) trials 292 293 The first proof-of-concept trial (meaning a trial in HCV-infected patients that 294 demonstrates initial activity as measured by reductions in HCV RNA from baseline 295 levels) should be a repeat-dose, randomized, dose-ranging, monotherapy trial, of 296 approximately 3 days duration, with collection of intensive PK, safety, and HCV RNA 297 decay data. Doses selected for phase 1b should be predicted to provide plasma drug 298 exposures expected to exceed, by several-fold, the protein binding-adjusted, cell culture 299 EC50 value of the agent for the relevant HCV genotype/subtype. Choice of doses should 300 also take into account safety margins identified in animal toxicology studies and in any 301 trials conducted in healthy volunteers. 302 303 Monotherapy exceeding 3 days is not recommended because data indicate resistant virus 304 is rapidly selected during monotherapy dosing with some DAA drug classes. 305 Furthermore, 3 days of monotherapy with a directly targeting anti-HCV agent is usually 306 sufficient for establishing proof of concept and for initial dose exploration. Selection of 307 resistance may limit the future utility of the new agent as well as other agents with similar 308 resistance pathways. In most cases, longer durations of monotherapy with directly 309 targeting anti-HCV agents are not appropriate because of resistance concerns, but can be 310 considered on a case-by-case basis depending on the characteristics of the individual 311 agent. In addition to limiting the duration of monotherapy, we recommend that phase 1 312 trials of initial activity be conducted in patients with CHC who are naïve to previous anti313 CHC therapy (including the agent under investigation), and who have minimal fibrosis 314 and no significant co-morbidities. Following demonstration of safety and antiviral 315 activity in treatment-naïve patients, sponsors can plan additional trials in treatment316 experienced patients. 317 318 Results from proof-of-concept trials can be used to guide dose selection for subsequent 319 phase 2 trials in which DAAs are studied for longer durations as part of a combination 320 regimen. We recommend that sponsors conduct mechanistic modeling of the 321 concentration-viral kinetics and the concentration-safety profile from phase 1 trials to 322 predict the most active and tolerable doses for study in phase 2. The mechanistic viral 323 kinetic model should describe time-dependent changes in HCV infection and the effect of 324 drug concentrations (Neumann, Lam, et al. 1998). The model should also include 325 components to describe virologic breakthrough, relapse, and long-term viral response 326 (e.g., SVR) to inform dose selection and treatment duration. In general, the model should 327 be used to inform dose selection and to reduce the risk of selecting for resistant virus 328 because of subtherapeutic exposure. 329 330 c. Phase 2 trials and dose-finding 331 332 A goal of early phase 2 trials is to begin to characterize the optimal dose and duration of 333 the DAA as part of combination regimens with regard to both activity and safety. 334
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335 The most straight-forward design for early phase 2 is a randomized controlled trial of 336 several doses of a DAA added to Peg-Interferon/RBV compared to a standard-of-care 337 regimen (consisting of Peg-Interferon/RBV). In general, trial patients should receive a 338 full course of treatment with the Peg-Interferon/RBV component (24 to 48 weeks 339 depending on early treatment responses); however, the DAA component can be 340 administered for shorter durations (e.g., 12 weeks, depending on results from phase 1b). 341 The dosing duration of the investigational agent in phase 2 trials should be based on 342 scientific and clinical rationale and not limited in duration only because long-term animal 343 toxicology studies have not been completed. 344 345 The U.S.-approved Peg-Interferon/RBV labels for treatment of HCV genotype 1 HCV 346 recommend 48 weeks of therapy; although in practice many clinicians shorten the course 347 for patients who have HCV RNA levels below the limit of detection at week 4 of 348 treatment. At present, the optimal duration of dosing a third drug in combination with 349 Peg-Interferon/RBV is not known and is likely to vary depending on characteristics of the 350 investigational agent and treatment population. Thus, various durations of treatment can 351 be evaluated in clinical trials. However, we generally recommend that phase 2 trials 352 include at least one treatment arm that evaluates 48 weeks of treatment with all 353 components of a regimen unless antiviral activity or safety data support a rationale for 354 shorter durations of the DAA component of the regimen. Evaluating shorter durations of 355 a regimen or a component of the regimen can also be accomplished by incorporating a 356 second randomization to assess treatment duration in those patients who have 357 demonstrated early virologic suppression. For example, one treatment strategy can allow 358 patients who reach undetectable HCV RNA by week 4 (RVR) and maintain undetectable 359 HCV RNA level at week 12 (extended RVR) to be re-randomized to receive a regimen of 360 24 versus 48 weeks in duration. Patients who do not attain extended RVR would receive 361 48 weeks of therapy in this example. 362 363 We recommend that sponsors conduct their first phase 2 combination trials with Peg364 Interferon/RBV in treatment-naïve patients as opposed to starting dose-finding in 365 treatment-experienced patients. Giving suboptimal doses to treatment-experienced 366 patients can further increase emergence of resistance and incomplete virologic response 367 to a DAA in combination with Peg-Interferon/RBV and this could jeopardize future 368 treatment regimens for those individuals. 369 370 Sustained virologic response should be the primary endpoint of the phase 2 trials; 371 however, analyses of 12 weeks of safety and antiviral activity data from the first 372 combination trial with Peg-Interferon/RBV in treatment-naïve patients can be used to 373 design larger phase 2b dose comparison trials to further characterize optimal dosing in 374 broader populations, including both treatment-naïve and treatment-experienced patients. 375 376 To provide the most meaningful comparisons for further development of a DAA, we 377 recommend phase 2 trial designs allow for direct comparisons between treatment arms 378 with respect to dose, strategy, and duration. For example, if two doses are evaluated, 379 both treatment doses should be evaluated for the same duration of therapy. 380
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381 Because the presence of an IL-28B genetic polymorphism has been shown to predict 382 substantial treatment response differences among patients receiving Peg-Interferon/RBV, 383 an effort should be made to collect samples for IL-28B testing at baseline to reduce the 384 potential for confounding in trial analyses. For example, in smaller dose-finding trials, 385 treatment arm imbalances in patients with the IL-28B polymorphism can confound 386 interpretation of trial results if sponsors do not consider the potential effect of this 387 predictive marker on treatment outcome. Sponsors should consider stratifying based on 388 IL-28B when DAAs are combined with Peg-Interferon/RBV in phase 2 and phase 3 389 trials. 390 391 d. Combination therapy with multiple DAAs 392 393 We encourage trials of DAAs with and without Peg-Interferon/RBV, depending on the 394 patient population. Trials of combinations of DAAs in patients who cannot tolerate 395 interferon or for whom interferon is contraindicated may address an unmet medical need. 396 Based on HCV replication dynamics in infected patients (Perelson 2009), the error-prone 397 nature of HCV genome replication, and the fact that the activity of a DAA is often 398 reduced by a single amino acid substitution in the drug target, multiple DAAs are needed 399 to suppress all pre-existing and emerging drug resistant variants to achieve SVR. At 400 present it is not known whether regimens that do not include interferon can produce SVR. 401 402 Ideally, agents with different mechanisms of action should be considered for combination 403 use. The information recommended to support combination trials using DAAs without 404 interferon and RBV includes: 405 406 • Combination antiviral activity data from cell culture 407 408 • Resistance and cross-resistance patterns for each agent in the combination 409 410 • Anti-HCV activity data from clinical trials (from short-term monotherapy trials or 411 from dose-finding in combination with Peg-Interferon/RBV) 412 413 • Some human safety data on each agent 414 415 • Justification for proposed doses based on clinical trials or other sources to indicate 416 doses chosen are likely to provide reasonable anti-HCV activity 417 418 • Drug-drug interaction data if the metabolism profiles suggest an interaction 419 potential between agents in the combination regimen 420 421 Some examples of potential designs for initial trials of combinations of DAAs include but 422 are not limited to the following: 423 424 • Randomized, controlled trials that compare short durations (less than 2 weeks) of 425 multiple DAAs in treatment-naïve patients followed by a full course of Peg426 Interferon/RBV either with or without one or more of the DAAs evaluated in the
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427 first 2 weeks. An approved Peg-Interferon/RBV regimen can be used as a control 428 arm. 429 430 • Randomized, controlled trials that compare several different dosing combinations 431 of multiple DAAs given for longer durations in treatment-naïve or -experienced 432 patients. This type of design includes frequent HCV RNA monitoring and 433 stopping rules for loss or lack of antiviral response. When enrolling treatment434 naïve patients or treatment-experienced patients who can tolerate interferon and 435 RBV, protocols can specify adding interferon and RBV to the DAA regimen after 436 a specified time point (e.g., 6 weeks) or at any other time if virologic rebound or 437 lack of complete virologic response is determined. 438 439 • A single-arm trial evaluating multiple doses of combination therapy before liver 440 transplant to study the overall antiviral effect before liver transplant and 441 potentially the effect on preventing infection of the transplanted liver. Response 442 rates can be compared to historical controls because transmission of HCV to a 443 transplanted liver in this setting is universal (Gane 2008), such that demonstrating 444 lack of infection in a substantial proportion of allograft recipients is meaningful. 445 446 Sponsors are encouraged to discuss with the FDA proposed development plans for 447 combination therapy of two or more DAAs. 448 449 e. Other phase 2 trial design considerations 450 451 Phase 2 trials can also be used to explore alternative dosing strategies of a DAA in 452 combination with other agents before confirmation of alternative dosing strategies in 453 larger phase 3 trials. Detailed rationale for an alternative dosing strategy should be 454 included with a phase 2 protocol submission. One example of an alternative dosing 455 strategy is a lead-in period with Peg-Interferon/RBV (before initiation of the new agent 456 as part of a three-drug therapy). One arm containing a lead-in period with Peg457 Interferon/RBV can be compared to another arm in which all drugs in the regimen were 458 started simultaneously. In theory, a lead-in strategy may be beneficial before starting a 459 DAA with a low genetic barrier to resistance because Peg-Interferon/RBV may reach a 460 steady-state by the time the new agent is added, reducing the possibility of combining the 461 agent in the setting of subtherapeutic Peg-Interferon/RBV exposures. The effects of 462 variations in dosing of a combination regimen, such as lead-in periods, can be explored in 463 phase 2 and confirmed in phase 3. 464 465 5. Efficacy Considerations 466 467 We recommend that sponsors analyze and provide summaries of SVR outcome data 468 (SVR12 and SVR24) from phase 2 to demonstrate that treatment responses are durable 469 and to allow for sample size calculations for phase 3 trials. 470 471 Sponsors can submit an NDA to gain approval of a drug in a single population, either 472 treatment-naïve or treatment-experienced patients. Such an application should include at
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473 least two adequate and well-controlled trials conducted in the proposed population 474 intended for labeling. Alternatively, sponsors can choose to pursue an indication for both 475 treatment-naïve and -experienced patients. In this circumstance, the NDA should contain 476 at least one adequate and well-controlled phase 3 trial in each patient population, with 477 adequate supporting data from phase 2 trials. 478 479 Trial designs for combinations of investigational DAAs without interferon and RBV 480 should include provisions for demonstrating that each component of the combination 481 therapy contributes to the desired effect. Establishing the contribution of each 482 component can be accomplished using factorial designs or modified factorial designs; 483 however, we acknowledge that factorial designs in which patients are randomized to only 484 one new DAA may not be appropriate because of emergence of resistance. As an 485 alternative to factorial designs, sponsors can show a DAA’s contribution toward efficacy 486 of a multiple DAA combination regimen using other types of data. Examples of data 487 supporting contribution of efficacy include but are not limited to the following: 488 489 • Cell culture data showing that DAA combinations slow or prevent the emergence 490 of resistance compared to single agents. 491 492 • Clinical trial data showing the efficacy of each new DAA in combination with 493 interferon and RBV. 494 495 • Comparisons of viral load reductions of short-term monotherapy trials (e.g., 3-day 496 trials) with viral load reductions of combination therapy in the same trial or across 497 other short-term trials. In this example, short-term viral load reductions in 498 patients given combination therapy with two DAAs should be substantially 499 greater than that observed in patients given the single agents. 500 501 • Early phase 2 clinical trial data showing that DAA combinations prevent or 502 reduce emergence of resistance. 503 504 Sponsors should consult 21 CFR 300.50 regarding combining drug products in a single 505 dosage form. 506 507 HCV treatment development plans may be eligible for consideration under 21 CFR part 508 312, subpart E, Drugs Intended to Treat Life-Threatening and Severely-Debilitating 509 Illnesses, fast track,10 or priority review if the specifics of the development plan justify 510 such an approach. 511 512 6. Safety Considerations 513 514 In general, we recommend that initial marketing applications for drugs intended to treat 515 CHC in patients without decompensated cirrhosis contain a safety database of
10 See the guidance for industry Fast Track Drug Development Programs — Designation, Development, and Application Review.
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516 approximately 1,000 to 1,500 patients exposed to the proposed dose and duration of 517 treatment. However, if significant safety signals emerge during drug development, the 518 safety database may need to be increased or specific safety studies may need to be 519 conducted. 520 521 For an indication in patients with decompensated cirrhosis or in patients who generally 522 have a high risk of morbidity and few if any treatment options, a safety database of 523 approximately 500 patients administered the DAA for the proposed dose and duration 524 may be sufficient for filing an NDA. We encourage sponsors to discuss their proposed 525 safety database before submitting an NDA. On occasion, specific findings in nonclinical 526 or clinical development may indicate the need for a database that is larger or longer in 527 duration to adequately evaluate potential drug toxicity. 528 529 We recommend that sponsors provide controlled and comparative safety data. Safety 530 data from uncontrolled protocols or treatment IND protocols may be useful, but often 531 lack the degree of detailed reporting obtained in controlled clinical trials. Moreover, the 532 assessment of causal relationships between a drug and an adverse event is more difficult 533 when relying on uncontrolled safety data and spontaneously occurring events or events 534 related to concurrent treatment or underlying illness may be attributed to the new drug. 535 536 B. Specific Efficacy Trial Design Considerations 537 538 1. Trial Design 539 540 Until the first DAA is approved, the recommended, and most straight-forward, design for 541 initial registration of a DAA is demonstration of superiority as an add-on to SOC, Peg542 Interferon/RBV, in a blinded comparison to placebo plus SOC. In the future, a 543 superiority design also can include a new drug as part of a four-agent regimen compared 544 to a three-agent regimen. Alternatively, an active-controlled noninferiority trial design 545 could be appropriate, comparing a new DAA plus Peg-Interferon/RBV to another 546 approved DAA (control) plus Peg-Interferon/RBV. The latter design is dependent on the 547 ability to define the contribution of the new active control to the Peg-Interferon/RBV 548 treatment so that a stringent noninferiority margin can be calculated. Sponsors 549 considering a noninferiority trial design should discuss in advance with the FDA 550 justification of the noninferiority margin, trial design, and the data analysis plan.11 551 552 Patients who achieve SVR should be followed for at least 3 years in larger phase 2 or 553 phase 3 trials to: (1) ensure durability of response; (2) determine whether subsequent 554 detection of HCV RNA represents outgrowth of pre-existing virus versus re-infection; 555 and (3) evaluate development of progressive liver disease and/or HCC. Long-term 556 follow-up can be provided as part of a postmarketing commitment following the initial 557 application.
11 For more information, see the draft guidance for industry Non-Inferiority Clinical Trials. When final, this guidance will represent the FDA’s current thinking on this topic. For the most recent version of a guidance, check the FDA Drugs guidance Web page at http://www.fda.gov/Drugs/GuidanceComplianceRegulatoryInformation/Guidances/default.htm.
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558 559 2. Trial Population 560 561 a. Patient enrollment definition 562 563 To be enrolled in a trial, patients should have CHC as documented by being tested: 564 565 • Positive for anti-HCV antibody, HCV RNA, or an HCV genotype at least 6 566 months before screening, and positive for HCV RNA and anti-HCV antibody at 567 the time of screening; or 568 569 • Positive for anti-HCV antibody and HCV RNA at the time of screening with a 570 liver biopsy consistent with chronic HCV infection (or a liver biopsy performed 571 before enrollment with evidence of CHC disease, such as the presence of fibrosis) 572 573 In addition to documentation of CHC, treatment-experienced patients should have 574 complete documentation of prior treatment history (including but not limited to 575 compliance with previous therapy and reasons for discontinuation), because these factors 576 may affect their response to retreatment. For the purpose of trial enrollment, the 577 following definitions are used to define the treatment experience of CHC patients, which 578 are based on previous responses to Peg-Interferon/RBV.12 579 580 • Naïve: received no prior therapy for HCV (including interferon or pegylated 581 interferon monotherapy) 582 583 • Null Responder13: less than 2 log10 reduction in HCV RNA at week 12 of a Peg584 Interferon/RBV 585 586 • Partial Responder: greater than or equal to 2 log10 reduction in HCV RNA at 587 week 12, but not achieving HCV RNA undetectable at end of treatment with a 588 Peg-Interferon/RBV 589 590 • Responder Relapser: HCV RNA undetectable at end of treatment with a 591 pegylated interferon-based regimen, but HCV RNA detectable within 24 weeks of 592 treatment follow-up 593 594 Note that HCV RNA undetectable for previous treatment response should have 595 been based on an assay that was considered sensitive at the time of treatment.
12 Patients who previously received interferon monotherapy or nonpegylated interferons plus RBV will be a diminishing proportion presenting for future trials. These patients can be categorized separately.
13 Other definitions for null response have been proposed, such as less than 1 log10 IU/mL decline in HCV RNA at week 4 of treatment. However, failure to achieve a greater than 2 log10 IU/mL HCV RNA decline at week 12 has typically been used as a treatment futility criterion and use of a null response definition of viral reduction less than 1 log10 IU/mL at week 4 causes a gap in classification for individuals with a viral load reduction greater than 1 log10 at week 4 but less than 2 log10 reduction at week 12.
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596 597 b. Patient enrollment biopsy considerations 598 599 Baseline biopsies can help to establish CHC diagnosis and can be useful for making 600 correlations between the amount of baseline fibrosis and subsequent treatment outcomes 601 such as SVR and occurrence of treatment-related adverse events. Correlations between 602 baseline fibrosis and efficacy or safety outcomes can provide useful information in 603 labeling. Sponsors should have a sufficient number of baseline biopsies throughout drug 604 development to explore correlations between fibrosis and outcomes. We recommend the 605 following regarding enrollment biopsies throughout drug development: 606 607 • For phase 1 trials in CHC patients and early phase 2 trials intended to evaluate 608 pharmacokinetics/pharmacodynamics (PK/PD) or initial efficacy and safety, a 609 liver biopsy may not be needed as long as patients fulfill the criteria for CHC 610 infection as described in the section above. 611 612 • For later phase 2 trials and phase 3 treatment-naïve trials, we recommend biopsies 613 within 2 to 3 years before enrollment. If cirrhosis has been previously 614 demonstrated on a biopsy, then biopsies obtained more than 3 years before 615 enrollment need not be repeated. 616 617 • For later phase 2 and 3 trials in treatment-experienced patients, a biopsy within 2 618 to 3 years may not be needed for trial enrollment; however, documentation of a 619 prior biopsy showing histological evidence of CHC should be available for 620 review. 621 622 • Biopsies can be waived for patients who would be placed at risk from the 623 procedure, such as patients with bleeding disorders. Inability to do a liver biopsy 624 should not exclude patients from a trial. 625 626 Noninvasive measures of hepatic fibrosis and disease activity assessments using 627 biochemical or scanning measurements are not considered validated and should not be a 628 substitute for the histological information yielded by liver biopsy. 629 630 3. Randomization, Stratification, and Blinding 631 632 We encourage sponsors to conduct double-blind trials whenever feasible. For add-on 633 superiority trials of a new DAA plus SOC compared to SOC alone, patients randomized 634 to SOC should receive a matching DAA placebo. It is appreciated that endpoints in these 635 trials are objective, but other aspects of the trial can be influenced by knowledge of 636 treatment assignment. In open-label protocols, patients may be more likely to drop out of 637 the trial if they know they are not receiving the new treatment or investigators could 638 provide different levels of encouragement to continue. 639 640 Sponsors should consider stratification of patients by important baseline factors such as 641 IL-28B polymorphisms, viral load (high or low), HCV genotype/subtype, and cirrhosis,
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642 because these baseline factors are predictive of SVR depending on the regimen and 643 population studied. In international trials, patients should be stratified by geographic 644 area. 645 646 4. Efficacy Endpoints 647 648 The primary endpoint for phase 3 studies should be SVR at 24 weeks after completion of 649 a scheduled course of therapy (SVR24). Viral RNA clearance should be measured using 650 a sensitive and specific quantitative assay. Before initiation of clinical trials, sponsors 651 should provide in their development plans the name and performance data for the assay 652 proposed for measuring HCV RNA viral load. 653 654 5. Trial Procedures and Timing of Assessments 655 656 Recommended key time points for measuring viral RNA are at weeks 4, 12, 24, and 48 or 657 at the end of therapy (which may occur at 24 or 48 weeks). Viral measurements at week 658 12 and 24 have been critical for deciding whether a full course of interferon/RBV is 659 justified. Week 4 and 12 measurements can be used in protocol decision making for 660 determining duration of a DAA or a regimen. 661 662 6. Statistical Considerations 663 664 a. Analysis populations 665 666 All patients who are randomized and receive at least one dose of assigned therapy during 667 the trial should be included in the primary efficacy analysis. If a substantial proportion of 668 patients exit the trial after randomization but before receiving treatment or if there is an 669 imbalance between treatment arms in the number of such patients, then sensitivity 670 analyses can be conducted imputing all or a proportion of those who exited as treatment 671 failures. 672 673 b. Efficacy analyses 674 675 The primary analysis endpoint should be SVR24, which measures the presence or 676 absence of viral RNA 24 weeks after completing a protocol-defined treatment course, and 677 this analysis determines whether effectiveness has been demonstrated.14 The primary 678 analysis should be adjusted for at least one or two of the most important covariates (e.g., 679 baseline HCV genotype, screening HCV RNA or IL-28B polymorphism). The covariates 680 that will be included in the primary analysis should be prespecified in the protocol. 681 682 For subgroup analyses, the analysis of SVR24 should be performed within important 683 demographic and baseline characteristics (e.g., geographic region (U.S., non-U.S.), sex, 684 race, age group, HCV genotype, screening serum HCV RNA, IL-28B status, baseline
14 Patients who discontinue therapy, for whatever reason, before the protocol-defined treatment duration can still be considered a responder if they have confirmed absence of HCV RNA 24 weeks after the originally planned treatment duration.
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685 weight, baseline body mass index, baseline alanine aminotransferase (ALT), baseline 686 liver histology, baseline fibrosis, and prior response to interferon/RBV-based regimens). 687 The purpose of these subgroup analyses basically is to evaluate the consistency of the 688 SVR24 endpoint result across these subgroups. It is important to recognize, however, 689 that simply by chance a hypothetical drug that has a homogeneous overall effect in a trial 690 population will almost invariably show statistically significant effects in some subgroups 691 and not in others in any given trial. Therefore, such subgroup results should be 692 interpreted with caution. 693 694 For meaningful subgroup analyses in treatment-experienced trials there should be 695 adequate representation from null responders, partial responders, and responder relapsers, 696 as appropriate for each drug based on activity observed in phase 2 data (phase 2 data may 697 suggest that it is futile to study certain categories of nonresponders in phase 3). 698 699 Secondary endpoints can include: 700 701 • Normalization of ALT levels 702 703 • The proportion of patients with RVR (undetectable HCV RNA after 4 weeks of 704 treatment) 705 706 • The proportion of patients with complete early virologic response (undetectable 707 HCV RNA after 12 weeks of treatment) 708 709 • The proportion of patients with undetectable levels of HCV RNA at the end of 710 treatment and 12 weeks after the end of treatment 711 712 • Relapse rates at 12 and 24 weeks after the end of treatment 713 714 However, secondary endpoints are not sufficient to support efficacy in the absence of an 715 effect on the primary endpoint. The protocol should propose a multiple testing strategy 716 for secondary endpoints that adjust for multiplicity to be applied after the result for the 717 primary endpoint is significant. 718 719 Patients who stop treatment because they did not completely suppress HCV RNA or had 720 rebound of HCV RNA after complete suppression should be regarded as failures in all 721 analyses. For patients who discontinue treatment early, sponsors should collect 722 information to determine if these patients switched treatments or added additional 723 therapy. This information can be used to understand reasons for discontinuation and how 724 patients will be included in the analysis. 725 726 c. Handling of missing data 727 728 For the primary analysis, sponsors should consider patients not to have achieved an SVR 729 if the patients discontinue from a trial before the end of the scheduled 24 week follow-up
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730 period and if the patients have missing HCV RNA values at the end of the scheduled 24 731 week follow-up period. 732 733 Sponsors should make every attempt to limit loss of patients from the trial, and when the 734 loss is unavoidable, to collect information that can help explain the cause of the loss and 735 the final status of the patient. Analyses excluding patients with missing data or other 736 post-treatment outcomes can be biased because patients who do not complete the trial 737 may differ substantially in both measured and unmeasured ways from patients who 738 remain in the trial. 739 740 A range of sensitivity analyses should be performed to demonstrate that the primary 741 analysis is robust to discontinuation and noncompliance. Sensitivity analyses can be 742 performed using various methods for imputing missing post-treatment virologic results at 743 24 weeks of follow-up. Examples include but are not limited to using results from any 744 available last post-treatment week in place of the 24-week follow-up visit or treating a 745 percentage of missing data as successes or failures based on the overall results in which 746 post-treatment data are available. 747 748 We recommend that sponsors collect detailed data on drug-adherence and confirmation 749 of reasons for discontinuation (e.g., opportunity to enter another trial offering a promising 750 new treatment, death or events leading to death, disease progression, adverse events, loss 751 to follow-up, withdrawal of consent, noncompliance, pregnancy, protocol violations, not 752 discontinued or not known to be discontinued but data were missing at the final visit). 753 The underlying reasons for discontinuation should be interpreted. For example, the 754 statistical analysis should include the number of patients who withdrew consent or were 755 lost to follow-up, or who had adverse events (e.g., nausea and diarrhea) that could have 756 been related to the treatment they were taking. 757 758 d. Interim analyses and data monitoring committees 759 760 If interim (or futility) analyses are performed, these analyses should be specified in the 761 statistical analysis plan (SAP). The purpose of the interim analysis should be stated in 762 the SAP. 763 764 The SAP should include provisions that ensure the interim analysis does not compromise 765 trial integrity. Sponsors should refer to ICH E9 when considering the use of interim 766 analyses in clinical trials. 767 768 Sponsors should consider using a data monitoring committee for phase 3 trials evaluating 769 treatments for CHC, particularly if there are potential safety issues with one or more 770 treatment arms. A detailed charter with the composition of the committee members and 771 the operational details should be provided for review.15 772
15 See the guidance for clinical trial sponsors Establishment and Operation of Clinical Trial Data Monitoring Committees.
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773 e. Statistical analysis plan 774 775 Before initiation of any phase 2b trial (larger phase 2 trial intended to be supportive of 776 efficacy for registration) or phase 3 trial, we recommend sponsors provide a detailed 777 SAP. The SAP can be either a separate document or be within the protocol. The SAP 778 should be considered as part of the protocol and ideally should be finalized together with 779 the protocol before patient enrollment. The SAP should have details on endpoint 780 ordering, the analysis population, the structure of statistical hypotheses to be tested, 781 methods and statistical models of analyses including the mathematical formulations, level 782 of significance or alpha-level, alpha adjustments for multiple comparisons and interim 783 analyses, and any planned covariates for the analyses. It is possible to modify an SAP as 784 long as the trial remains blinded, but sponsors should recognize that a detailed discussion 785 may be needed concerning data access and appropriate firewalls for maintaining the 786 integrity of the blind. 787 788 It is important that the SAP prospectively identify the covariates to be used in the 789 analysis. It is also important that the number of covariates be kept to a minimum and 790 limited to those that are expected to strongly influence outcome. 791 792 Center-by-treatment interaction should be investigated and reported to assess consistency 793 of the efficacy results. 794 795 C. Other Considerations 796 797 1. Clinical Virology Considerations 798 799 Proof-of-concept and efficacy trials should assess the development of HCV genotypic 800 resistance to the investigational agent. Resistance testing should be performed for 801 patients who demonstrate virologic breakthrough (defined as a greater than or equal to 1 802 log10 increase in HCV RNA above nadir, or detectable HCV RNA, while on treatment, 803 after an initial drop to below detection), an incomplete antiviral response (e.g., detectable 804 HCV RNA at end of treatment), a slow or plateau viral load decay phase, or virologic 805 relapse after treatment cessation. Any changes, including mixtures, in the amino acid 806 coding sequence of the targeted genome region present in on-treatment or follow-up 807 samples, but not in the baseline sample, should be reported as having developed during 808 therapy. In addition, baseline samples should be analyzed to identify HCV genetic 809 polymorphisms that are associated with differential antiviral activity with the new agent. 810 811 Viral resistance-associated polymorphisms or substitutions observed in clinical trials but 812 not identified and characterized in nonclinical virology experiments should be evaluated 813 phenotypically by introducing the changes into the HCV genome, and determining the 814 conferred fold-shift in susceptibility to the agent using appropriate cell culture and/or 815 biochemical assays. In addition, phenotypic analyses should be performed using baseline 816 and on-treatment clinical isolates from a subset of trial patients representative of the HCV 817 genetic diversity and virologic responses observed in clinical trials. 818
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819 Emerging data with new DAAs suggest resistance-associated substitutions may persist 820 for long periods of time in the absence of drug selection. Because DAAs within the same 821 drug class typically have overlapping resistance profiles, the persistence of resistance822 associated substitutions can significantly limit a patient’s future treatment options. 823 Therefore, patients who have detectable resistance-associated substitutions at treatment 824 cessation or follow-up should be followed for an extended period, preferably at least 1 825 year after treatment cessation, to assess the persistence of resistance-associated 826 substitutions. The potential persistence of resistance-associated substitutions should be 827 characterized for patients enrolled in phase 1 and phase 2 clinical trials so that 828 preliminary long-term follow-up data are obtained by the time of completion of phase 3 829 trials. Genotyping methodology should be capable of assessing the quantity of resistant 830 viruses during the outgrowth of wild-type virus. 831 832 Sponsors should consider genotyping regions outside the direct HCV genome target 833 depending on the characteristics of the antiviral agent and interactions of the target with 834 other viral proteins. In cases when resistance is suspected based on viral RNA kinetics, 835 but genotypic evidence of resistance is not detected, sponsors should also consider 836 performing additional genotypic analyses using a method sufficiently sensitive to detect 837 minority variants.16 838 839 2. PK/PD Considerations 840 841 Trials conducted in HCV-infected patients should include assessment of 842 pharmacokinetics and the relationship between exposure and virologic success and 843 toxicity in all patients. 844 845 Sponsors can use a combination of dense and sparse sampling throughout development to 846 characterize the pharmacokinetics of the investigational agent. For example, a dense 847 sampling schedule should be implemented in monotherapy trials. In longer term trials, 848 however, a dense sampling schedule might not be feasible. Alternatively, sparse 849 sampling from these trials can be combined with dense PK data from earlier trials for 850 analysis. Sparse PK samples should be obtained at the time of key virologic assessments, 851 such as weeks 4, 12, 24, and 48. These data can then be subjected to appropriate 852 population PK analysis.17 PK samples for evaluation of Peg-Interferon/RBV or any other 853 agent in the regimen should also be collected in trials of combination therapy to assist in 854 exposure-response analyses. 855 856 Sponsors can use the following two broad approaches to characterize the relationship 857 between exposure and viral kinetics or virologic success of the investigational agent, 858 depending on the stage of development and purpose of the analysis. Both approaches
16 Additional guidance for reporting HCV drug resistance can be found in the guidance for industry
Antiviral Product Development — Conducting and Submitting Virology Studies to the Agency: Guidance for Submitting HCV Resistance Data.
17 See the guidance for industry Population Pharmacokinetics.
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859 allow for exploration of relevant covariates. These analyses should also account for the 860 development of resistance to the investigational agent. 861 862 (1) To aid the design of phase 2b or phase 3 trials, with respect to dose and regimen 863 choice, a mechanistic approach relating drug concentrations and viral kinetics is 864 most appropriate. Specifically, sponsors should develop a viral kinetic model that 865 describes time-dependent changes in HCV infection during treatment, includes a 866 mechanistically appropriate targeted drug effect, and, includes components to 867 describe virologic breakthrough, relapse, and long-term viral response. 868 869 (2) When sufficient SVR12 or SVR24 data are available, a simplified analysis 870 relating proportion of patients with virologic success and appropriate exposure 871 variable (e.g., Cmin or area under curve) can be used to support evidence of 872 effectiveness and justify dose selection.18 873 874 3. Special Populations 875 876 Treatments for patients with hepatic impairment or pre- or post-transplant patients, 877 patients co-infected with HIV and HCV, and patients with decompensated cirrhosis are 878 unmet medical needs. We strongly encourage sponsors to discuss early in development 879 the process to determine appropriate timing for initiating trials in these populations. 880 881 a. Hepatic impairment 882 883 A hepatic impairment trial to inform the need for dose modifications should be conducted 884 early in development so that patients with hepatic impairment can be included in phase 2 885 and 3 trials, as appropriate. These data also can support use in pre- or post-transplant 886 patients. 887 888 b. HIV/HCV co-infected patients 889 890 It is estimated that nearly 30 percent of patients with HIV are co-infected with HCV 891 (Sulkowski 2008). Patients with HIV/HCV co-infection are at higher risk of more rapid 892 progression of liver disease than patients with HCV infection alone. In addition, 893 treatment responses (SVR24) with SOC in co-infection are generally less than responses 894 (SVR24) with HCV infection alone. 895 896 As needed, and based on a particular investigational drug’s metabolic profile, drug-drug 897 interaction trials should be conducted before trials in co-infected patients to support 898 concomitant dosing of a new HCV drug and antiretroviral drugs. 899 900 We strongly suggest that an initial NDA for the treatment of HCV contain some clinical 901 data on the HIV/HCV co-infected population at time of filing, including:
18 See the guidance for industry Exposure-Response Relationships — Study Design, Data Analysis, and Regulatory Applications.
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902 903 • Drug-drug interaction data with the most commonly used HIV drugs 904 905 • Safety data on a cohort of co-infected patients receiving the drug for the 906 recommended treatment duration 907 908 • Preliminary efficacy data characterizing, at minimum, on-treatment responses 909 910 With the above-mentioned preliminary data, labeling describing drug interactions and 911 preliminary safety data may be appropriate. For more extensive labeling that expands the 912 indication to the HIV co-infected population or includes a description of efficacy in the 913 co-infected population, a clinical trial demonstrating efficacy and safety in at least 300 914 co-infected patients may be appropriate. In some cases, single-arm prospective trials 915 (with historical controls) may be appropriate for the co-infected population if trials in the 916 HCV mono-infected population showed robust and substantial efficacy of the new DAA 917 added to SOC. Trials in co-infected patients should evaluate SVR at 24 weeks after end 918 of therapy as the primary efficacy endpoint. As part of the safety evaluation, loss of HIV 919 efficacy (rebounds in HIV viral RNA) should be assessed. 920 921 c. Patients with decompensated cirrhosis 922 923 SOC, interferon-based regimens are not considered appropriate for patients with 924 decompensated cirrhosis or for most patients pre- or post-liver transplant; therefore, 925 treatment with multiple investigational DAAs is likely to be needed to achieve viral 926 suppression. Because there are currently no HCV treatments in patients with 927 decompensated cirrhosis and because spontaneous resolution of HCV infection in this 928 population is consistently negligible, dose-response trials or historically controlled 929 efficacy and safety trials showing clinically significant SVRs may be appropriate to 930 expand the labeling for this population. However, as more drugs become available for 931 study in combination regimens, we will encourage comparative trials. SVR24 should be 932 the primary efficacy endpoint, but other important endpoints include progression of liver 933 disease, transplantation, and mortality. SVR24 is an important endpoint notwithstanding 934 disease progression requiring transplantation, because SVR24 will likely translate into 935 prevention of infection of a newly transplanted liver. 936 937 The contribution of each agent toward overall efficacy of a regimen should be 938 demonstrated, but can be based on data such as that discussed in section III.B.6, 939 Statistical Considerations. For example, trials showing the efficacy of one new DAA 940 added to Peg-Interferon/RBV in patients with compensated cirrhosis can serve as 941 supportive data for demonstrating contribution toward efficacy in other populations that 942 are more difficult to study. 943 944 Plans for expanded access trials or safety trials should also be considered for this 945 population early in development. 946
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947 d. Pediatric populations 948 949 Early trials of DAAs should enroll adult patients only, reserving pediatric exposure until 950 the pharmacokinetics, pharmacodynamics, and safety of the agent are reasonably well951 defined. Sponsors are encouraged to begin discussions of their pediatric formulation and 952 clinical development plan early in development, but pediatric clinical trials should be 953 initiated once phase 2 adult data characterizing the safety profile and initial antiviral 954 efficacy are available. If clinical trials in adults have demonstrated no safety concern 955 specific to a histologic stage, liver biopsies are not recommended for routine entry criteria 956 into pediatric trials. If biopsies are done because they are clinically indicated, biopsy data 957 should be provided. 958 959 4. Early Access/Treatment INDs 960 961 Some hepatitis C-infected patients who have not responded to approved treatments and/or 962 who are at substantial risk of liver disease progression may benefit from access to new 963 therapeutic options before their approval. Treatment INDs or other access protocols for 964 DAAs may be appropriate when sufficient clinical trial data have been generated to 965 characterize a reasonably safe and active dose of an investigational agent. Ideally, the 966 timing of a treatment IND would occur after phase 3 trials were fully enrolled or well 967 underway so as not to interfere with phase 3 drug development. Treatment INDs can 968 provide early access while phase 3 trials are being completed, analyzed, submitted, and 969 reviewed by the FDA. Alternatively, individual patient INDs and treatment access 970 protocols for intermediate size populations may be possible. In contrast to treatment 971 INDs for larger populations during or after phase 3 trials, access for intermediate size 972 populations (approximately 100 patients or fewer), can occur earlier in drug 973 development. 974 975 Historically, early access programs with HIV allowed many people to gain access to life976 saving drugs. However, for some individuals, early access to a drug resulted in what 977 amounted to sequential monotherapy and the emergence of multidrug resistance. 978 Because treatment of CHC requires multiple agents to achieve SVR and to reduce the 979 emergence of drug resistance to single agents or drug classes, treatment INDs that include 980 two or more investigational agents or that allow co-enrollment in several treatment IND 981 programs simultaneously are desirable, particularly for previous null responders or for 982 patients who cannot take interferon-based regimens. However, treatment use of multiple 983 investigational agents should be supported by: 984 985 • Data and rationale that characterize the potential for PK drug interactions and 986 potential for overlapping toxicity. Data to support dose modifications if drug 987 interactions are present. 988 989 • Information suggesting the potential for additive or synergistic activity and no or 990 minimal overlapping resistance profiles. 991
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992 Refer to section III.A.4.d., Combination therapy with multiple DAAs, for the data needed 993 to support treatment use of multiple investigational agents. 994
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995 GLOSSARY OF ACRONYMS 996 997 CHC chronic hepatitis C 998 DAA direct-acting antiviral agent 999 HCC hepatocellular carcinoma 1000 HCV hepatitis C virus 1001 HCV RNA hepatitis C virus ribonucleic acid 1002 HIV human immunodeficiency virus 1003 IFN interferon 1004 IL interleukin 1005 Peg pegylated 1006 RBV ribavirin 1007 RVR rapid virologic response 1008 SOC standard of care 1009 SVR sustained virologic response 1010 SVR24 sustained virologic response 24 weeks after stopping treatment 1011
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1012 REFERENCES 1013 1014 Arase, Y, K Ikeda, F Suzuki, Y Suzuki, S Saitoh, M Kobayashi, N Akuta, T Someya, R 1015 Koyama, T Hosaka, H Sezaki, M Kobayashi, H Kumada, 2007, Long-Term Outcome 1016 After Interferon Therapy in Elderly Patients With Chronic Hepatitis C, Intervirology, 1017 50(1):16-23. 1018 1019 Braks, RE, N Ganne-Carrie, H Fontaine, J Paries, V Grando-Lemaire, M Beaugrand, S 1020 Pol, JC Trinchet, 2007, Effect of Sustained Virological Response on Long-Term 1021 Clinical Outcome in 113 Patients With Compensated Hepatitis C-Related Cirrhosis 1022 Treated By Interferon Alpha and Ribavirin, World J Gastroenterol, Nov 14, 1023 13(42):5648-53. 1024 1025 Bruno, S, T Stroffolini, M Colombo, S Bollani, L Benvegnù, G Mazzella, A Ascione, T 1026 Santantonio, F Piccinino, P Andreone, A Mangia, GB Gaeta, M Persico, S Fagiuoli, 1027 PL Almasio; Italian Association of the Study of the Liver Disease (AISF), 2007, 1028 Sustained Virological Response to Interferon-Alpha Is Associated With Improved 1029 Outcome in HCV-Related Cirrhosis: A Retrospective Study, Hepatology, Mar, 1030 45(3):579-87. 1031 1032 Gane, EJ, 2008, The Natural History of Recurrent Hepatitis C and What Influences This, 1033 Liver Transpl., Suppl2: S36-44. 1034 1035 Ge, D, J Fellay, AJ Thompson, JS Simon, KV Shianna, TJ Urban, EL Heinzen, P Qiu, 1036 AH Bertelsen, AJ Muir, M Sulkowski, JG McHutchison, DB Goldstein, 2009, Genetic 1037 Variation in IL-28B Predicts Hepatitis C Treatment-Induced Viral Clearance, Nature, 1038 461:399-401. 1039 1040 Ghany, MG, DB Strader, DL Thomas, LB Seeff, 2009, Diagnosis, Management, and 1041 Treatment of Hepatitis C: An Update, Hepatology, 49:1335-1374. 1042 1043 Imai, Y, S Kawata, S Tamura, I Yabuuchi, S Noda, M Inada, Y Maeda, Y Shirai, T 1044 Fukuzaki, I Kaji, H Ishikawa, Y Matsuda, M Nishikawa, K Seki, Y Matsuzawa, 1998, 1045 Relation of Interferon Therapy and Hepatocellular Carcinoma in Patients With 1046 Chronic Hepatitis C, Osaka Hepatocellular Carcinoma Prevention Study Group, Ann 1047 Intern Med, Jul 15, 129(2):94-9, PMID: 9669992. 1048 1049 Kim, WR, 2002, The Burden of Hepatitis C in the United States, Hepatology, 1050 36(Suppl):S30-S34. 1051 1052 Manos, MM, WK Zhao, VA Shvachko, N Volkova, CP Quesenberry, Viral Hepatitis 1053 Registry, Kaiser Permanente Division of Research, Oakland, CA, 2009, Long Term 1054 Outcomes in Patients Treated With Peg-Interferon/Ribavirin Therapy for Hepatitis C: 1055 The Substantial Effect of Sustained Viral Response (SVR) on Liver Disease, Mortality 1056 and Diabetes, 13th International Symposium on Viral Hepatitis and Liver Disease, 1057 Abstract PL-3.
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1058 Neumann, AU, NP Lam, H Dahari, DR Gretch, TE Wiley, TJ Layden, AS Perelson, 1059 1998, Hepatitis C Viral Dynamics In Vivo and the Antiviral Efficacy of Interferon1060 alpha Therapy, Science, Oct 2, 282(5386):103-7. 1061 1062 Okanoue, T, Y Itoh, M Minami, S Sakamoto, K Yasui, M Sakamoto, K Nishioji, Y 1063 Murakami, K Kashima, 1999, Interferon Therapy Lowers the Rate of Progression to 1064 Hepatocellular Carcinoma in Chronic Hepatitis C but not Significantly in an Advanced 1065 Stage: A Retrospective Study in 1148 Patients, Viral Hepatitis Therapy Study Group, 1066 J Hepatol, Apr, 30(4):653-9, PMID: 10207807. 1067 1068 Perelson, AS, 2009, HCV Kinetics, 13th International Symposium on Viral Hepatitis and 1069 Liver Disease, Washington, DC. 1070 1071 Shiratori, Y, Y Ito, O Yokosuka, F Imazeki, R Nakata, N Tanaka, Y Arakawa, E 1072 Hashimoto, K Hirota, H Yoshida, Y Ohashi, M Omata; Tokyo-Chiba Hepatitis 1073 Research Group, 2005, Antiviral Therapy for Cirrhotic Hepatitis C: Association With 1074 Reduced Hepatocellular Carcinoma Development and Improved Survival, Ann Intern 1075 Med, Jan 18, 142(2):105-14, PMID: 15657158. 1076 1077 Sulkowski, MS, 2008, Viral Hepatitis and HIV Coinfection, J Hepatol, Feb, 48(2):3531078 67. 1079 1080 Veldt, BJ, EJ Heathcote, H Wedemeyer, J Reichen, WP Hofmann, S Zeuzem, MP 1081 Manns, BE Hansen, SW Schalm, HL Janssen, 2007, Sustained Virologic Response 1082 and Clinical Outcomes in Patients With Chronic Hepatitis C and Advanced Fibrosis, 1083 Ann Intern Med, 147:677-684. 1084 1085 Yoshida, H, Y Arakawa, M Sata, S Nishiguchi, M Yano, S Fujiyama, G Yamada, O 1086 Yokosuka, Y Shiratori, M Omata, 2002, Interferon Therapy Prolonged Life 1087 Expectancy Among Chronic Hepatitis C Patients, Gastroenterology, Aug, 123(2):4831088 91. 1089 1090 Yoshida, H, Y Shiratori, M Moriyama, et al., 1999, Interferon Therapy Reduces the Risk 1091 for Hepatocellular Carcinoma: National Surveillance Program of Cirrhotic and 1092 Noncirrhotic Patients With Chronic Hepatitis C in Japan, IHIT Study Group, 1093 Inhibition of Hepatocarcinogenesis by Interferon Therapy, Ann Intern Med, Aug 3, 1094 131(3):174-81. 1095
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