A phase 3, randomized trial to evaluate lot-to-lot consistency of V116, an adult-specific pneumococcal conjugate vaccine (STRIDE-4).

Background: Streptococcus pneumoniae infection can lead to community-acquired pneumonia and invasive pneumococcal disease (IPD), conditions associated with substantial morbidity and mortality. V116 (Merck & Co., Inc., Rahway, NJ, USA) is a 21-valent, adult-specific pneumococcal conjugate vaccine (PCV) indicated for protection against pneumonia and IPD caused by S. pneumoniae.

Methods: This global phase 3 trial (ClinicalTrials.gov: NCT05464420) evaluated the manufacturing consistency of V116. Adult participants were randomly assigned to receive a single dose of V116 from one of three lots or the 23-valent pneumococcal polysaccharide vaccine (PPSV23). Serotype-specific opsonophagocytic activity (OPA) geometric mean titers (GMTs) were assessed 30 days post-vaccination. Immunoglobulin G (IgG) geometric mean concentrations (GMCs) and geometric mean fold rises for OPA and IgG responses were also evaluated. Solicited systemic and injection site adverse events (AEs) were collected for 5 days post-vaccination, serious AEs were reported throughout study participation, and all other AEs were reported for 30 days post-vaccination.

Findings: All three lots of V116 met equivalence criteria based on OPA GMTs for all 21 serotypes. OPA GMTs and IgG GMCs were comparable between the combined V116 lots and PPSV23 for shared serotypes and were higher in the combined V116 lots for serotypes unique to V116. AEs were similar across the three lots of V116 and between the combined V116 lots and PPSV23.

Conclusions: V116 exhibited immunogenicity and safety profiles that were consistent across three manufacturing lots.

Funding: Funding for this research was provided by Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.