Merck’s CAPVAXIVE demonstrates positive immune responses in adults

Merck announced results from STRIDE-8, a Phase 3 trial evaluating CAPVAXIVE, at IDWeek 2024 in Los Angeles, California. The trial evaluated the immunogenicity, safety and tolerability of CAPVAXIVE compared to PCV15 (pneumococcal 15-valent conjugate vaccine) in combination with PPSV23 (pneumococcal 23-valent polysaccharide vaccine) in vaccine-naive adults 18-64 years of age with certain chronic conditions that put them at an increased risk of pneumococcal disease. Key findings from the STRIDE-8 trial include: CAPVAXIVE was immunogenic for all 21 serotypes (or strains) included in the vaccine, as measured by serotype-specific opsonophagocytic activity geometric mean titers (primary immunogenicity objective) and immunoglobulin G geometric mean concentrations (secondary immunogenicity objective) at Day 30; Immune responses elicited by CAPVAXIVE were comparable to PCV15 followed by PPSV23 for the 13 common serotypes and higher for the eight serotypes unique to CAPVAXIVE, as measured by serotype-specific OPA GMTs and IgG GMCs 30 days post-vaccination; The proportions of participants with adverse events, including injection-site, systemic, and vaccine-related AEs, were numerically lower in the V116 + placebo group than in the PCV15 + PPSV23 group.