Novavax reports positive RSV vaccine Phase II clinical trial results

Novavax, Inc., announced on Tuesday that top-line data from a Phase II dose-ranging clinical trial of its respiratory syncytial virus vaccine candidate in women childbearing age accomplished the trial's protocol-specified objective and supported progression to the next stage of advanced clinical testing.

The trial was seen as an important step in establishing the safety and immunogenicity of the vaccine candidate for use in a maternal immunization strategy.

In the proposed strategy, antibodies in vaccinated women would be expected to naturally be transferred to infants in utero and may confer passive protection at the earliest stage of life when infants are extremely vulnerable to RSV.

"These results confirm that our RSV vaccine candidate has the potential to induce clinically useful immunity and has raised no safety concerns," Gregory Glenn, Novavax's senior vice president and chief medical officer, said. "The primary immunogenicity measures confirmed that the vaccine is a potent antigen and the aluminum phosphate adjuvant further enhanced the antibody responses. The results answered key questions regarding dose regimens and the use of aluminum phosphate as adjuvant.

"With respect to secondary and exploratory objectives, we also observed that the vaccine induced peak neutralizing antibodies in excess of those seen in our Phase I trial, as well as reproducing palivizumab-like antibody responses. Neutralizing antibodies have been associated with decreased risk of hospitalization in infants and palivizumab is a licensed monoclonal antibody, marketed as Synagis, that is used to prevent high-risk infant hospitalization due to RSV. The findings from this clinical trial indicate that our RSV F vaccine candidate has the potential to induce functional immune responses at levels that would be predicted to protect infants through maternal immunization. Overall, we are buoyed by these data and believe these findings warrant the pursuit of later-stage clinical trials."