A Phase I clinical study conducted by Novavax has demonstrated positive top-line results of its respiratory syncytial virus (RSV) fusion (F) recombinant nanoparticle vaccine candidate.

The blinded placebo-controlled dose-escalating Phase I trial enrolled 150 healthy adults, aged from 18 to 49 years old, who were allocated to six cohorts that included 4 dose levels of vaccine.

The study is intended to assess the safety and tolerability of aluminum phosphate-adjuvanted (adjuvant) and unadjuvanted formulations of its RSV vaccine candidate, while evaluating total and neutralising anti-RSV antibody responses and the impact of the adjuvant.

Novavax RSV vaccine candidate demonstrated high antibody response, a significant dose-response pattern, high rates of seroconversion at all doses including a rate of 100% at the highest-dose-adjuvant group, and a higher plaque reduction neutralising titers in all the vaccine groups containing adjuvant.

Novavax president and CEO Stanley Erck said the clinical data provides a pathway to move forward in studying the vaccine candidate in infants, young children and older adults affected by RSV.

Novavax senior vice president and chief medical officer Gregory Glenn said the findings from the Phase I trial are consistent with the preclinical results in relevant animal models, which indicated the vaccine candidate was well-tolerated, highly immunogenic and produced functional antibodies that neutralised RSV.