The reemergence of H7N9 in China during the past month has reinforced the need for a vaccine. Candidates from Chinese and Taiwanese manufacturers have grabbed the headlines recently, but now a U.S. player, Novavax ($NVAX), has joined the race with positive Phase I data.
Novavax reported a summary of the results in a letter to The New England Journal of Medicine. The trial enrolled 284 people in Australia and gave them a placebo or one of 6 H7N9 vaccine formulations. Based on the antibody responses, Novavax thinks two shots of 5µg of antigen will protect four-in-five people when given with 60 ISCO units of CSL's Iscomatrix adjuvant. Higher antigen doses were given without the adjuvant, but using smaller quantities increases the number of available vaccines.
In a pandemic situation, when manufacturing can be a bottleneck, this is important, and observers are encouraged by the data. "These are very preliminary results, but it appears for the first time that we may have a vaccine that would work against an outbreak [of avian flu]. This is a very important milestone. We have a promising vaccine where before we had none," Biomedical Advanced Research and Development Authority (BARDA) director Robin Robinson told Reuters.
Robinson also talked up the expected benefits of using virus-like particle vaccines instead of traditional egg-based production methods. The response to swine flu in 2009 was hamstrung by production delays, the fixing of which the U.S. government has prioritized. Computer models used by BARDA show Novavax could produce a vaccine 12 weeks after the start of an outbreak and have 50 million doses available within four months.
Novavax expects to start a U.S. clinical trial of its H7N9 vaccine in the first half of next year. A trial of Sanofi's ($SNY) H7N9 vaccine in conjunction with adjuvants from GlaxoSmithKline ($GSK) and Novartis ($NVS) is already underway.