Novavax reports positive results from Phase II study of trivalent VLP influenza vaccine in older adults

Novavax, Inc. (Nasdaq: NVAX) reported today that its trivalent seasonal influenza virus-like-particle (VLP)-based vaccine candidate was safe and immunogenic against the 2009-2010 seasonal influenza virus strains in older adults 60 years or higher in age.

In a double-blind, active-controlled Phase II study of 480 randomized subjects, the safety, tolerability and immunogenicity of a single 15 microgram dose or 60 microgram dose (per strain) of trivalent influenza VLP was compared to a dose of a commercially available inactivated trivalent influenza vaccine (TIV). The primary immunogenicity measure in the study was hemagglutination inhibition (HAI) antibody response induced by the vaccine 21 days after immunization.  At both the high (60 microgram) and low (15 microgram) dose, the VLP vaccine showed no significant increase in severe local or systemic adverse events.  

While the study was not powered to obtain definitive differences in immunogenicity between VLP doses or establish non-inferiority between VLPs and TIV, a preliminary analysis of immunogenicity results showed that the 60 microgram dose of trivalent VLP vaccine induced a statistically significant higher seroconversion rate than TIV against one of the three 2009-2010 strains of seasonal influenza virus and showed no statistically significant difference from TIV in the seroconversion rate against the other two strains.  The 15 microgram dose of trivalent VLP vaccine did not induce significantly different seroconversion rates than TIV for two of the three strains, but induced a significantly lower seroconversion rate compared to TIV against one of the strains.

These immunogenicity responses observed in the VLP vaccine groups will be used to guide the selection of a dose most likely to meet or exceed the U.S. and European regulatory guidelines for immunogenicity and safety criteria for licensure of the vaccine for older adults.  

Dr. Rahul Singhvi, President and CEO of Novavax, stated:  "We are pleased to see that both doses of VLP vaccine were well tolerated and immunogenic in older adults, which was a key question for this trial.   The finding that a higher dose of VLP vaccine could be more immunogenic in this population is particularly important since there is a significant medical need for a better vaccine for older adults.  These data show that our recombinant, VLP-vaccine technology affords great flexibility in using dose as a means to improve the possible effectiveness of the vaccine.  The data from this clinical trial and from our recent Phase II influenza vaccine study in healthy younger adults suggest that our trivalent influenza vaccine may be effective in a broad range of subjects.  Taken together, the findings from these studies are encouraging and will be useful for planning further clinical testing of our trivalent VLP influenza vaccine."