A Phase 3, Randomized Trial Investigating the Safety, Tolerability, and Immunogenicity of V116, an Adult-Specific Pneumococcal Conjugate Vaccine, in Pneumococcal Vaccine-Naïve Adults 18–64 Years of Age at Increased Risk of Pneumococcal Disease, STRIDE-8

BACKGROUND: Pneumococcal disease (PD) is a major cause of hospitalization and mortality in adults. Individuals with certain chronic illnesses are at increased risk for PD. METHODS: This phase 3, randomized, double-blind, active comparator-controlled trial (NCT05696080) evaluated the safety and immunogenicity of 21-valent pneumococcal conjugate vaccine (V116) in adults 18-64 years of age with ≥1 condition associated with increased risk of PD (diabetes mellitus or kidney, heart, liver, or lung disease). Participants were given a single dose of either V116 followed by placebo or 15-valent pneumococcal conjugate vaccine (PCV15), followed by 23-valent pneumococcal polysaccharide vaccine (PPSV23) 8 weeks later. Immune responses were evaluated by opsonophagocytic activity (OPA) geometric mean titers (GMTs) and immunoglobulin G (IgG) geometric mean concentrations (GMCs) at 30 days postvaccination (day 30 for V116; week 12 for PCV15 + PPSV23). Proportions of participants who experienced adverse events (AEs) within 5 days postvaccination and serious AEs (SAEs) or deaths during the study were assessed. RESULTS: V116 was immunogenic for all 21 serotypes contained in the vaccine. OPA GMTs and IgG GMCs following V116 vaccination were comparable to PCV15 + PPSV23 for the 13 serotypes common between vaccine groups. For the eight serotypes unique to V116, immune responses were higher following V116 compared with PCV15 + PPSV23. V116 was well tolerated compared with PCV15 + PPSV23; no vaccine-related SAEs or deaths were reported. CONCLUSIONS: V116 elicits robust immune responses and is well tolerated in adults 18-64 years of age with conditions associated with an increased risk of PD.