Novavax Announces Positive Top-Line Data from Dose-Confirmatory Phase 2 Clinical Trial of RSV Vaccine,

Vaccine candidate was well-tolerated with no vaccine-related serious adverse events Highest immune responses observed with a single dose of vaccine combined with aluminum phosphate adjuvant Women with the lowest baseline levels of RSV neutralizing antibodies had the largest increases following immunization, consistent with prior data Palivizumab-like antibodies exceeded levels observed in previous trials High levels of antibodies developed within 14 days after immunization and persisted over the 91-day observation period Data permit selection of vaccine formulation and regimen for planned Phase 2 clinical trial in pregnant women Novavax, Inc.

today announced positive top-line safety and immunogenicity data from its RSV-F protein nanoparticle vaccine candidate in a Phase 2 clinical trial in women of childbearing age. The randomized, blinded, placebo-controlled Phase 2 study was designed to evaluate the immunogenicity and safety of multiple formulations of Novavax' RSV-F protein nanoparticle vaccine adjuvanted with aluminum phosphate. The primary outcome of the trial was safety and immune response (measured by levels of serum IgG antibody specific for the F protein). The study enrolled 720 healthy women between the ages of 18 and 35 years, who received either one or two intramuscular injections featuring two different dose levels of vaccine antigen with a range of doses of aluminum phosphate adjuvant. These top-line data relate to the safety and immunogenicity over the 91-day period following first immunization and support Novavax' maternal immunization strategy. Highlights of the interim results: The RSV-F vaccine candidate was well-tolerated, with no vaccine-related serious adverse events, at all doses and formulations. The safety profile was consistent with data from prior Phase 1 and 2 studies. Significant increases in RSV-F antibody levels were observed across all doses and formulations, consistent with prior studies. Peak RSV-F antibody levels were observed in the group that received a single dose of vaccine containing 120 µg of antigen with one-third of the aluminum phosphate dose used in prior studies. Clear increases in RSV neutralizing antibodies were also shown across all doses and formulations, and were strongest in women entering the study with the lowest baseline levels, in confirmation of prior studies. Vaccine-induced palivizumab-like antibody levels demonstrated strong concordance with anti-RSV-F antibody responses. A single 120 µg antigen dose generated peak palivizumab-like antibody levels of approximately 400 µg/mL, the highest levels seen in any study. Kinetic analysis of the antibody responses showed rapid increases in antibody levels in all vaccine formulations and dosing regimens. A single 120 µg antigen dose generated peak RSV-F and palivizumab-like antibody levels within 14 days of immunization, and high levels of both were sustained through the 91-day observation period. "Our vaccine has again performed in a highly consistent manner from a safety and immunogenicity perspective. In testing for an optimal formulation, we have delivered improved immunogenicity in a one-dose regimen. We believe such a regimen will improve patient convenience, vaccine uptake and compliance, thus decreasing the burden of RSV disease. In addition, we believe that the rapid and sustained antibody response displayed by a single-dose formulation of our vaccine provides significant flexibility for administration during pregnancy," said Gregory Glenn M.D., Senior Vice President Research and Development at Novavax. "Together with our previous clinical trial in women of childbearing age, these data support our first maternal immunization trial, currently projected for the 4th quarter of 2014. We have requested a Type C meeting with the FDA this summer, at which time we will discuss our suite of pre-clinical and clinical data in support of our application to proceed to studies in pregnant women." This clinical trial is being conducted in collaboration with PATH, an international nonprofit organization that drives transformative innovation to save lives and improve health. PATH committed funding of approximately $3.5 million to support this trial with the aim of advancing the development of an RSV vaccine to protect infants through maternal immunization in low-resource countries. Novavax expects to present the entire date-set at an appropriate scientific forum in the future. About RSV RSV is a respiratory pathogen that afflicts all humans regardless of age. In healthy adults, RSV infections are generally mild to moderate in severity, but may be more severe in infants and young children as well as the elderly and adults with underlying chronic cardiac or pulmonary disease. Globally, RSV is a common cause of childhood respiratory infection, with a disease burden of 64 million cases and approximately 160,000 deaths annually. Severe RSV disease results in 3.4 million hospital admissions per year globally and disproportionately affects infants below six months of age. It is estimated that between 11,000 to 17,000 elderly and high risk adults die of RSV infection annually in the U.S., with up to 180,000 hospitalizations for serious respiratory symptoms. Currently, there is no approved RSV prophylactic vaccine available for either of these populations. About Novavax