Safety and immunogenicity of a Sf9 insect cell-derived respiratory syncytial virus fusion protein nanoparticle vaccine

ObjectiveWe performed a Phase 1 randomized, observer-blinded, placebo-controlled trial to evaluate the safety and immunogenicity of a recombinant respiratory syncytial virus (RSV) fusion (F) protein nanoparticle vaccine.MethodsSix formulations with (5, 15, 30 and 60 μg) and without (30 and 60 μg) aluminum phosphate (AdjuPhos) were administered intramuscularly on day 0 and 30 in a dose escalating fashion to healthy adults 18–49 years of age. Solicited and unsolicited events were collected through day 210. Immunogenicity measures taken at day 0, 30 and 60 included RSV A and B microneutralization, anti-F IgG, antigenic site II peptide and palivizumab competitive antibodies.ResultsThe vaccine was well-tolerated, with no evident dose-related toxicity or attributable SAEs. At day 60 both RSV A and B microneutralization was significantly increased in vaccinees versus placebo. Across all vaccinees there was a 7- to 19-fold increase in the anti-F IgG and a 7- to 24-fold increase in the antigenic site II binding and palivizumab competitive antibodies.ConclusionsThe RSV F nanoparticle vaccine candidate was well tolerated without dose-related increases in adverse events. Measures of immunity indicate that neutralization, anti-RSV F IgG titers and palivizumab competing antibodies were induced at levels that have been associated with decreased risk of hospitalization.NCT01290419.

► This Phase 1 trial evaluated the safety and immunogenicity of an RSV (F) nanoparticle vaccine.
► The vaccine was well-tolerated and no related SAEs were observed.
► Both RSV A and B microneutralizating antibodies were increased in vaccinees versus placebo.
► There was a 7- to 19-fold increase in anti-F IgG and a 7- to 24-fold increase in palivizumab-like antibodies.
► The levels of immunity are similar to those seen in other settings with decreased hospitalizations.