Idenix Pharmaceuticals Initiates Proof-of-Concept Study for Protease Inhibitor IDX320 in Hepatitis C Patients

News Release


Idenix Pharmaceuticals Initiates Proof-of-Concept Study for Protease Inhibitor IDX320 in Hepatitis C Patients


CAMBRIDGE, Mass., June 10, 2010 /PRNewswire via COMTEX/ --Idenix Pharmaceuticals, Inc. (Nasdaq: IDIX), a biopharmaceutical company engaged in the discovery and development of drugs for the treatment of human viral diseases, today announced that it has initiated a 3-day proof-of-concept study of IDX320, a protease inhibitor for the treatment of hepatitis C virus (HCV) infection, under a Clinical Trial Application (CTA). The study is evaluating IDX320 in treatment-naive hepatitis C genotype 1-infected patients.


"The potent and multi-genotypic activity demonstrated in vitro,as well as the favorable pharmacokinetics observed in healthy volunteers, suggests a promising profile for further development of IDX320," said Jean-Pierre Sommadossi, Ph.D., chief executive officer of Idenix. "The landscape for combination development in HCV is evolving quickly. Assuming favorable results from the IDX320 proof-of-concept study, we plan to discuss with regulatory agencies a direct-acting antiviral combination strategy with IDX320 and IDX184, our HCV nucleotide polymerase inhibitor."


Douglas Mayers, M.D., Idenix's chief medical officer commented, "We are encouraged by the results seen to date with IDX320 and are hopeful that future clinical studies will allow us to continue advancing this program with the ultimate goal of treating a wide range of patients infected with HCV."


The proof-of-concept trial in HCV-infected patients is a Phase I/II randomized, parallel-arm, double-blind, placebo-controlled study evaluating the safety and antiviral activity of IDX320 in treatment-naive adult patients infected with chronic hepatitis C. The study will evaluate four doses of IDX320, ranging from 50 to 400 mg once-per-day, administered for three days. Each cohort of the study will evaluate eight patients randomized six to IDX320 and two to placebo.


About IDX320


IDX320, a macrocyclic HCV protease inhibitor, is an inhibitor of NS3/4A proteases from genotypes 1a, 1b, 2a and 4a (IC50 values from 0.8 to 1.9 nM), as well as from genotype 3a (IC50=23 nM). IDX320 did not inhibit nine tested cellular proteases (IC50 > 10 uM) in vitro, suggesting high selectivity. IDX320 bound tightly to the HCV protease enzyme with a long dissociation half-life (> 9 hours). After single 2 mg/kg oral doses of IDX320 in two animal species, favorable bioavailability and a long plasma half-life were observed, with substantial plasma concentrations 24 hours post dose. Comparable drug exposure was confirmed in healthy volunteers (n=6) receiving a single 200 mg oral dose. Further, no significant in vitro inhibition of human drug metabolizing enzymes, CYP450s and UGT1A1, by IDX320 suggests low potential for drug-drug interactions in patients.


About IDX184


IDX184 is a novel, liver-targeted nucleotide prodrug of 2'-methyl guanosine monophosphate, which includes Idenix's proprietary liver-targeting technology. This technology enables the delivery of nucleoside monophosphate to the liver, leading to the formation of high levels of nucleoside triphosphate, potentially maximizing drug efficacy and limiting systemic side effects with low, once-daily dosing. IDX184 in combination with pegylated interferon and ribavirin has demonstrated a generally favorable safety profile and potent antiviral activity in an ongoing Phase IIa study.


News Release


Idenix Pharmaceuticals Reports Progress on Clinical Programs and First Quarter 2010 Financial Results


CAMBRIDGE, Mass., May 3, 2010 /PRNewswire via COMTEX/ --Idenix Pharmaceuticals, Inc. (Nasdaq: IDIX), a biopharmaceutical company engaged in the discovery and development of drugs for the treatment of human viral diseases, today reported unaudited financial results for the first quarter ended March 31, 2010. At March 31, 2010, Idenix's cash, cash equivalents and marketable securities totaled $33.8 million.


Research and Development Highlights


Phase IIa: IDX184, a liver-targeted hepatitis C virus (HCV) nucleotide prodrug


* In April 2010, Idenix announced interim data from an ongoing 14-day phase IIa study evaluating its lead HCV drug candidate, IDX184, a liver-targeted HCV nucleotide prodrug, in combination with pegylated interferon and ribavirin (PegIFN/RBV) in treatment-naive HCV genotype 1-infected patients. Patients receiving 50 and 100 mg of IDX184 in combination with pegylated interferon and ribavirin (PegIFN/RBV) demonstrated potent antiviral activity at 14 days with mean (+/- standard deviation) viral load reductions of 1.2 (+/- 1.1) log(10) IU/mL in the placebo cohort (n=8), 2.7 (+/- 1.3) log(10) IU/mL in the 50 mg IDX184 QD cohort (n=16), 4.0 (+/- 1.7) log(10) IU/mL in the 50 mg IDX184 BID cohort (n=8) and 4.2 (+/- 1.9) log(10) IU/mL in the 100 mg IDX184 QD cohort (n=8). Fifty percent of subjects receiving a total daily dose of 100 mg IDX184 achieved undetectable virus levels by Day 14. The side effect profile of IDX184 combined with PegIFN/RBV has been consistent with the laboratory and side effect profile of PegIFN/RBV. The most common adverse events reported were fatigue, myalgia, headache and nausea. Enrollment of the 150 mg once-daily cohort is now complete.


Phase I: IDX320, an HCV protease inhibitor


* In the first quarter of 2010, Idenix completed a double-blind, placebo-controlled phase I clinical trial evaluating single and multiple ascending doses of its HCV protease inhibitor, IDX320, in healthy volunteers. A three-day proof-of-concept study in treatment-naive HCV genotype 1-infected patients is expected to begin in the second quarter.


Phase I: IDX375, an HCV non-nucleoside polymerase inhibitor


* In the first quarter of 2010, Idenix continued the phase I clinical trial evaluating higher single and multiple doses of the free acid form of IDX375 in healthy volunteers. The company expects that these studies in healthy volunteers will be followed by a three-day proof-of-concept study in treatment-naive genotype 1-infected patients in the second half of 2010.


Phase IIb: GSK2248761/IDX899, a non-nucleoside reverse transcriptase inhibitor


* GSK2248761, for the treatment of HIV-1, has progressed through long-term chronic toxicology studies and drug-drug interaction studies in healthy volunteers. Idenix was notified by ViiV Healthcare Company, an affiliate of GlaxoSmithKline (GSK), that an operational preclinical milestone triggering a $6.5 million payment related to the development of GSK2248761 was achieved. GSK anticipates a broad phase IIb clinical development program to begin in 2010.


"We are pleased with the continued clinical progress of our broad pipeline of hepatitis C drug candidates from three major HCV drug classes," said Jean-Pierre Sommadossi, Ph.D., chairman and chief executive officer of Idenix. "With the anticipated completion of the 14-day phase IIa clinical trial of IDX184 and the three-day proof-of-concept study of IDX320 by mid-year 2010, we believe we will be a step closer toward exploring our first combination study utilizing these two direct-acting antiviral drug candidates."


Sommadossi continued, "We are excited to see the further advancement of GSK2248761 in the ViiV Healthcare pipeline. We look forward to the initiation of the phase IIb program this year."


First Quarter 2010 Financial Results


For the first quarter ended March 31, 2010, Idenix reported total revenues of $2.7 million, compared to total revenues of $4.0 million in the first quarter of 2009. The company reported a net loss of $16.2 million, or a loss of $0.24 per basic and diluted share, for the first quarter ended March 31, 2010, compared to a net loss of $12.9 million, or a loss of $0.23 per basic and diluted share for the first quarter ended March 31, 2009.


During the first quarter of 2010, Idenix initiated a plan to restructure its operations at the company's research facility in Montpellier, France to reduce its workforce by approximately 17 positions in connection with its ongoing cost saving initiatives. In the first quarter of 2010, Idenix recorded charges of $2.2 million for employee severance costs related to the Montpellier facility restructuring together with charges related to an earlier reduction of the company's United States workforce by 13 positions in January 2010. Idenix expects the restructurings to result in annualized savings of approximately $3.0 million to $4.0 million.


On April 29, 2010, Idenix announced the pricing of an underwritten offering of 6,460,672 shares of its common stock at a price of $4.35 per share. After the underwriting discount and estimated offering expenses payable by the company, the company expects to receive net proceeds of approximately $26.2 million. All of the shares are being sold by Idenix. The offering is expected to close on May 4, 2010, subject to customary closing conditions.


2010 Financial Guidance


The company expects that its current cash, cash equivalents and marketable securities, together with the anticipated royalty payments associated with product sales of Tyzeka(R)/Sebivo(R) (telbivudine), proceeds from the recent offering and the milestone payment from ViiV Healthcare Company can fund operations into the second half of 2011. This guidance assumes no additional milestone payments, license fees, reimbursement for development programs and no financing activities.


Conference Call and Webcast Information


Idenix will hold a conference call today at 4:30 p.m. ET. To access the call please dial (800) 471-3635 U.S./Canada or (706) 758-9475 International and enter passcode 70646639. To listen to a live webcast of the call, go to "Calendar of Events" in the Idenix Investor Center at www.idenix.com. Please log in approximately 10 minutes before the call to ensure a timely connection. A replay of the conference call and webcast will be available until May 17, 2010. To access the replay, please dial (800) 642-1687 U.S./Canada or (706) 645-9291 International and enter the passcode 70646639.


About Idenix


Idenix Pharmaceuticals, Inc., headquartered in Cambridge, Massachusetts, is a biopharmaceutical company engaged in the discovery and development of drugs for the treatment of human viral diseases. Idenix's current focus is on the treatment of patients with chronic hepatitis C infection. For further information about Idenix, please refer to www.idenix.com.