Novavax said today it has won a grant of up to $89 million from the Bill & Melinda Gates Foundation, to be used toward development of the respiratory syncytial virus (RSV) F Vaccine.
The grant will support a Phase III clinical trial of the RSV F Vaccine in pregnant women, set to begin during the first quarter of 2016. The funding will also support regulatory licensing efforts, providing a path to prequalification by the World Health Organization (WHO). Novavax has agreed to make the RSV F Vaccine affordable and accessible to people in developing countries upon winning licensure.
“Maternal immunization may provide protective antibodies to infants during the first few months of life, and we hope this vaccine will protect infants from this disease to help them live healthy, productive lives,” Keith Klugman, M.D., Ph.D., director of the foundation’s Pneumonia Program, said in a statement.
RSV is the most common cause of lower respiratory tract infections and the leading viral cause of severe lower respiratory tract disease in infants and young children worldwide. A 2010 study estimated the annual global RSV infection rate at 64 million, with a mortality rate of 160,000.
There is no approved RSV vaccine available. MedImmune’s monoclonal antibody Synagis® (palivizumab)—which gained initial U.S. approval in 1998—targets the RSV F protein and is indicated for prevention of serious lower respiratory tract disease caused by RSV in children at high risk of RSV disease.
Novavax announced the Gates Foundation grant at the same time it disclosed positive top-line data from a Phase II trial of the vaccine. Women in the vaccinated group demonstrated a geometric mean 14-fold rise in anti-F IgG, a 29-fold rise in palivizumab-competing antibody (PCA), and a 2-fold rise in microneutralization titers, the company said.
Women who received placebo demonstrated no significant change in their antibody levels, Novavax added.
In infants, the estimated half-life of anti-F IgG was 30 days—a duration that rose to 34 days for RSV/B, 36 days for RSV/A, and 41 days for anti PCA.
“As anticipated, infants received a significant bolus of all anti-RSV antibodies via transplacental transfer. Half of all hospitalizations due to RSV occur within the first three months of life, and based on these data, the RSV F Vaccine demonstrates the potential to protect infants when they are most at risk of infection,” Gregory Glenn, M.D., svp, research and development of Novavax.
The Phase II trial assessed the safety and immunogenicity of the RSV F Vaccine in 50 healthy pregnant women in their third trimester. Trial participants were randomized to receive either 120 mcg of RSV-F Vaccine adjuvanted with 0.4 mg of aluminum phosphate or placebo.
The women were followed through the remainder of their pregnancies, delivery, and for an additional 180 days postpartum to assess safety and immunogenicity as measured by serum RSV anti-F IgG, microneutralizing, and PCA titers.
Also studied during the trial were the transplacental transfer of maternal antibodies induced by the vaccine, the impact of maternal immunization on infant safety during the first year of life, and RSV-specific antibody levels through the infants’ first six months of life.
“Our groundbreaking Phase II results in both maternal and older adult target populations, underscore the promise of our RSV F Vaccine programs,” stated Novavax president and CEO Stanley C. Erck. “We look forward to carrying our recent momentum into the fourth quarter as we prepare to initiate two pivotal Phase III trials of our RSV F Vaccine.”