A Randomized, Double‐Blind, Placebo‐Controlled, Phase 1 Study to Evaluate the Safety, Reactogenicity, and Immunogenicity of Single Vaccination of Ad26.RSV.preF‐Based Regimen in Japanese Adults Aged 60 Years and Older

Abstract

ABSTRACTBackgroundRespiratory syncytial virus (RSV) is increasingly recognized as a significant cause of lower respiratory tract disease (LRTD) in older adults. The Ad26.RSV.preF/RSV preF protein vaccine demonstrated protective efficacy against RSV related LRTD in a Phase 2b study in the United States. Hence, Ad26.RSV.preF/RSV preF protein vaccine candidate was evaluated in the Japanese older adult population.MethodsThis Phase 1 study evaluated safety, reactogenicity, and immunogenicity of Ad26.RSV.preF/RSV preF protein vaccine at dose level of 1 × 1011 vp/150 μg in Japanese healthy adult aged ≥60 years. The study included a screening Phase, vaccination, 28‐day follow up Phase, a 182‐day follow‐up period, and final visit on Day 183. A total of 36 participants were randomized in a 2:1 ratio to receive Ad26.RSV.preF/RSV preF protein vaccine (n = 24) or placebo (n = 12). After study intervention administration, the safety and immunogenicity analysis were performed as per planned schedule. Immune responses including virus‐neutralizing and preF‐specific binding antibodies were measured on Days 1, 15, 29, and 183.ResultsThere were no deaths, SAEs, or AEs leading to discontinuation reported during the study. The Ad26.RSV.preF/RSV preF protein vaccine had acceptable safety and tolerability profile with no safety concern in Japanese older adults. The Ad26.RSV.preF/RSV preF protein vaccine induced RSV‐specific humoral immunity, with increase in antibody titers on Days 15 and 29 compared with baseline which was well maintained until Day 183.ConclusionsA single dose of Ad26.RSV.preF/RSV preF protein vaccine had an acceptable safety and tolerability profile and induced RSV‐specific humoral immunity in Japanese healthy adults.Trial RegistrationNCT number: NCT04354480; Clinical Registry number: CR108768.