Novavax, Inc. announced topline data from two clinical trials of its RSV F-protein recombinant nanoparticle vaccine candidate (RSV F Vaccine) in older adults. The Resolve™ trial, a Phase 3 trial of our RSV F Vaccine in 11,856 older adults (60 years of age and older), did not meet the pre-specified primary or the secondary efficacy objectives, and did not demonstrate vaccine efficacy. Consistent with our previous clinical experience, the vaccine was well tolerated.
The trial was a randomized, observer-blinded, placebo-controlled trial conducted at 60 sites in the United States. The primary objective of the Resolve trial was to demonstrate efficacy in the prevention of moderate-severe RSV-associated lower respiratory tract disease (RSV msLRTD), as defined by the presence of multiple lower respiratory tract symptoms. The secondary objective of the trial was to demonstrate efficacy of the RSV F Vaccine in reducing the incidence of all symptomatic respiratory disease due to RSV (RSV ARD). Finally, the trial also evaluated the safety of the unadjuvanted, 135 microgram dose of the RSV F Vaccine compared to placebo.
“We are both surprised and disappointed by the outcome of the Resolve trial, which we recently unblinded. Our initial analyses and review of the key aspects of the trial do not indicate issues with trial execution, data collection, data integrity, or drug product quality. We expect to have preliminary immunogenicity data in the coming weeks to further our understanding of the trial results,” said Gregory Glenn M.D., President, Research and Development. “Historically, annual seasonal RSV ARD attack rates between 3% and 7% have been observed in older adults. In our Phase 2 trial, we observed an RSV ARD attack rate of 4.9% and an RSV msLRTD attack rate of 1.8%. In contrast, we observed an RSV ARD attack rate of 2.0% and an msLRTD attack rate of 0.4% in our Phase 3 trial. These attack rates indicate a mild RSV season in older adults this year. We are continuing to investigate potential root causes that could have impacted the outcome of this trial. We continue to believe that there is a path forward for our RSV vaccine and that there is an important unmet need for an RSV vaccine in older adults.”