Reviewers: data support accelerated approval for adjuvanted flu vaccine

FDA reviewers said immunogenicity and safety data from two Phase III trials fulfill immunogenicity criteria to support accelerated approval of Q-Pan H5N1 adjuvanted vaccine from GlaxoSmithKline plc (LSE:GSK; NYSE:GSK). In the Q-Pan-H5N1-001 and Q-Pan-H5N1-002 trials, the injectable adjuvanted influenza vaccine met the primary immunogenicity endpoints based on a surrogate marker -- vaccine induced hemagglutination-inhibition (HAI) -- that is "reasonably likely" to predict clinical benefit. The comments came in briefing documents released ahead of Wednesday's Vaccines and Related Biological Products Advisory Committee to discuss a BLA for the product. The committee will also discuss the postmarketing approaches by which GSK can confirm the clinical benefit of Q-Pan H5N1, which is under review to prevent disease in adults who are at an increased risk of exposure to the influenza A virus subtype H5N1. GSK submitted the application in February; the PDUFA date is not disclosed.

The reviewers said observational data for the FluLaval unadjuvanted H1N1 vaccine from GSK were "not adequate to provide a reliable vaccine effectiveness estimate" to support traditional approval of Q-Pan H5N1. GSK said it submitted the FluLaval observational data, which were collected during the 2009 H1N1 pandemic, because it was not feasible to collect clinical endpoint data for Q-Pan H5N1 in the absence of a pandemic strain. In February, GSK said that during a pre-BLA meeting last year, FDA had agreed that effectiveness of Q-Pan H5N1 could be inferred from the FluLaval data because both vaccines use the same manufacturing process and have similar immunogenicity data. FDA granted FluLaval accelerated approval based on immunogenicity data, but GSK has not yet verified the product's clinical benefit. ...