Novartis Says Swine Flu Vaccine Works Quickly

Novartis Says Swine Flu Vaccine Works Quickly

Sept 3 2009 MedPage Today

A vaccine against the H1N1 pandemic flu was safe and immunogenic within two weeks after a single dose, according to the Swiss drugmaker Novartis AG.

The vaccine, developed using a cell-culture method, is the second to show single dose immunogenicity, after China's Sinovac Biotech reported similar results Aug. 31.

The Sinovac drug, to be given in a 15-microgram dose without adjuvant, was approved to day by the Chinese State Food and Drug Administration. The vaccine, dubbed Panflu, is approved for people ages 3 to 60, according to the Chinese official news agency Xinhua.

The Novartis vaccine, dubbed Celtura, was tested for safety and immunogenicity in a 100-volunteer study run by the University of Leicester and University Hospitals of Leicester in England.

In the trial, the vaccine -- boosted with the adjuvant MF-59 -- was given in one or two doses of 7.5 micrograms each, the company said in a statement.

Serum antibody responses were highest among volunteers who got two doses but a single dose also yielded responses deemed to be protective against the flu.

Specifically, hemagglutination-inhibition titers reached 1:40 or higher in 80% of those getting a single dose and more than 90% of those getting two doses.

Additional clinical trials sponsored by Novartis -- intended t o include more than 6,000 adults and children -- are already under way, the company said.

"The pilot trial results are encouraging," according to Andrin Oswald, MD, chief executive officer of Novartis Vaccines and Diagnostics.

"The study suggests that while two doses seem to provide better protection, one dose of our adjuvanted Celtura vaccine may be sufficient to protect adults against the swine flu," he said in a statement.

The vaccine against the seasonal flu usually elicits an immune response with a single shot, because of lingering immunity from previous exposures both to vaccines and seasonal strains.

But health officials have been concerned that few people have any immunity to the pandemic H1N1 strain, so that two doses would be required to obtain any protection.

Given the short time available to produ ce the vaccine, such a requirement might mean a shortfall in available drug.