Merck, known as MSD outside the U.S. and Canada, announced positive results from its Phase 3 STRIDE-13 trial evaluating CAPVAXIVE, its 21-valent pneumococcal conjugate vaccine, in children and adolescents with chronic medical conditions that increase their risk of pneumococcal disease.
Presented at the 6th European Society of Clinical Microbiology and Infectious Diseases (ESCMID) Conference on Vaccines, the trial assessed CAPVAXIVE’s safety, tolerability, and immune response in participants aged 2 to under 18 years who had already received a pediatric pneumococcal vaccine regimen.
Key Findings:
- Robust Immune Response: CAPVAXIVE generated immune responses against all 21 serotypes included in the vaccine, as measured 30 days post-vaccination.
- Noninferior and Superior Results: It was noninferior to PPSV23 for the 12 shared serotypes and superior for the nine additional serotypes unique to CAPVAXIVE.
- Comparable Safety: Adverse events, including serious and systemic reactions, were generally similar between CAPVAXIVE and PPSV23 groups.
“These results demonstrate the potential of CAPVAXIVE to deliver broader protection for children and adolescents at higher risk for pneumococcal disease,” said Dr. Rotem Lapidot, Chief of Pediatric Infectious Diseases at Rambam Health Care Campus and a trial investigator.
Currently approved for adults in the U.S. and other global markets, CAPVAXIVE covers serotypes responsible for around 84% of invasive pneumococcal disease (IPD) cases in adults 50+—a broader range than PCV20. In the pediatric high-risk population (ages 2–17), it potentially covers about 78% of IPD cases, with 11 serotypes not included in infant vaccines accounting for approximately 34% of cases.
“This trial marks a significant step in expanding CAPVAXIVE’s potential use,” said Dr. Paula Annunziato, SVP of Infectious Diseases and Vaccines at Merck Research Laboratories. “These findings reinforce our goal of expanding access to pneumococcal protection across age groups.”
The STRIDE-13 results represent the final readout from Merck’s STRIDE Phase 3 program and will be submitted to global health authorities for potential label expansion to younger age groups.