An Indirect Treatment Comparison (ITC) and Matching-adjusted Indirect Comparison (MAIC) Between a 15-valent (V114) and a 20-valent (PCV20) Pneumococcal Conjugate Vaccine Among Healthy Infants

Objectives: Immunogenicity between 15-valent V114 (PCV15) and 20-valent PCV20 pneumococcal conjugate vaccines in healthy infants is compared in an indirect treatment comparison and matching-adjusted indirect comparison. Hypotheses: immunogenicity of V114 is non-inferior to PCV20 for all PCV13 serotypes, and superior to PCV20 for serotype 3 based on lower bound margins.

Methods: Two phase 3 pivotal studies on 3 + 1 pediatric vaccination schedule at age 2, 4, 6, and 12-15 months compared V114 ( = 858) to PCV13 ( = 856) and PCV20 ( = 1001) to PCV13 ( = 987). Infant's age and race in V114 study were matched to those in PCV20 study. Primary endpoints were serotype-specific Immunoglobulin G (IgG) response rate difference (RRD) 30 days post-dose (PD)3; IgG geometric mean concentration (GMC) ratios 30 days PD3 and PD4.

Results: V114 was non-inferior (>-10%-point; >0.5) to PCV20 (p-value <0.001) for all endpoints. V114 was superior ( >0%-point; >1.2) to PCV20 (p-value <0.001) for serotype 3: RRD was 34.5% (95%CI 27.9%-41.1%) PD3, and IgG GMC ratios were 2.39 (95%CI 2.12-2.68) PD3 and 2.15 (95%CI 1.90-2.41) PD4.

Conclusion: Immune response to V114 administered in a 3 + 1 schedule in healthy infants was considered non-inferior to PCV20 for all 13 PCV13 serotypes and superior for serotype 3 PD3 and PD4.

Clinical Trial Registration: www.clinicaltrials.gov identifiers NCT03893448, NCT04382326.