Clinical-stage biopharmaceutical company Novavax has begun enrolment in the phase two dose-ranging trial of its respiratory syncytial virus (RSV) vaccine candidate in women of childbearing age.

The randomised, blinded, placebo-controlled study is designed to evaluate the immunogenicity and safety of two dose levels of Novavax’s RSV-F protein nanoparticle vaccine, with and without aluminum phosphate as an adjuvant.

Novavax senior vice president and chief medical officer Gregory Glenn said the study will determine the optimal dosing regimen for future studies and the potential adjuvant effect of aluminum phosphate besides the evaluation of the safety and immunogenicity of RSV vaccine candidate in an important patient population.

"Previous clinical and preclinical findings have suggested that immunization with our nanoparticle vaccine produces functional neutralizing antibodies to multiple sites on the F protein," Glenn added.

"We expect to report top-line results from this trial, through day 56 observations, in the first quarter of 2013."

The study is being conducted in collaboration with PATH, an international nonprofit organisation that will fund approximately $2m to support the trial.

Around 330 women of childbearing age are expected to be enrolled in the study and will receive either one or two intramuscular injections at each dose level of vaccine or placebo at days 0 and 28.

According to the study design, the safety and immunogenicity will be evaluated over six and four month periods, respectively.

Image: The electron micrograph of the Respiratory Syncytial Virus (RSV) pathogen. Credit: CDC/ Dr. Erskine Palmer.