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Safety and Immunogenicity of a Pneumococcal Conjugate Vaccine When Administered Concomitantly With Routine Pediatric
Sylvie Pichon1, Gary M Ullery2, Luis Cousin3
1From the Global Clinical Development, Sanofi, Marcy l'Étoile, France.
Insights
A new 21-valent pneumococcal conjugate vaccine (PCV21) shows promising safety and robust immunogenicity against Streptococcus pneumoniae, including additional serotypes compared to PCV13. Further evaluation of a high-antigen formulation is recommended for Phase 3 trials.
Area of Science:
- Immunology
- Vaccinology
- Pediatric Infectious Diseases
Background:
- Development of a 21-valent pneumococcal conjugate vaccine (PCV21) to broaden coverage against Streptococcus pneumoniae.
- PCV21 includes 13 serotypes from PCV13 plus 8 additional serotypes.
- Evaluation of 3 PCV21 formulations versus PCV13 in pediatric populations.
Purpose of the Study:
- To assess the safety and immunogenicity of PCV21 formulations compared to PCV13.
- To compare different antigen content levels within PCV21 formulations.
- To evaluate PCV21 in both previously vaccinated toddlers and unvaccinated infants.
Main Methods:
- A randomized, modified double-blind, multicenter, active-controlled Phase 2 study.
- Two cohorts: toddlers previously vaccinated with PCV13 and unvaccinated infants.
- Concomitant administration with routine pediatric vaccines; immunogenicity assessed post-vaccination.
Main Results:
- All PCV21 formulations demonstrated safety profiles comparable to PCV13.
- PCV21 elicited robust immune responses across all targeted Streptococcus pneumoniae serotypes.
- PCV21 showed numerically greater immunogenicity for additional serotypes compared to PCV13, with higher antigen content correlating with increased response.
Conclusions:
- PCV21 exhibits favorable immunogenicity and a good safety profile.
- The PCV21 formulation with the highest antigen content for selected serotypes warrants further investigation in Phase 3 studies.
Background:
A 21-valent pneumococcal conjugate vaccine, PCV21, was developed to provide broader coverage against Streptococcus pneumoniae serotypes. PCV21 comprises 13 serotypes common to a licensed 13-valent pneumococcal conjugate vaccine (PCV13) and 8 additional serotypes. This study evaluated 3 PCV21 formulations with differences in antigen content for some serotypes, compared with PCV13, administered concomitantly with routine pediatric vaccines.
Methods:
This was a randomized, modified double-blind, multicenter, active-controlled phase 2 study enrolling toddlers previously vaccinated with 3 doses of PCV13 (cohort 1) and unvaccinated infants (cohort 2). Toddlers/infants were randomized 1:1:1:1 to 1 of 3 PCV21 formulations or PCV13, administered at ages 12-15 months (cohort 1) and 2, 4, 6 and 12-15 months (cohort 2). Safety was assessed throughout the study. Immunogenicity was assessed 30 days after dose 1 (cohort 1) or doses 3 and 4 (cohort 2).
Results:
Overall, 140 toddlers (cohort 1) and 712 infants (cohort 2) were randomized. All PCV21 formulations showed acceptable safety profiles comparable with PCV13. In both cohorts, serotype-specific immunoglobulin G concentrations showed that PCV21 elicited a robust immune response for all serotypes. PCV21 and PCV13 showed generally comparable immunogenicity for shared serotypes, with numerically greater immunogenicity in the PCV21 groups than in the PCV13 group for the additional serotypes. Increased antigen content for selected serotypes appeared to be associated with greater immunogenicity.
Conclusion:
PCV21 demonstrated favorable immunogenicity, with no safety concerns identified. This study supports the evaluation of the PCV21 formulation that had the highest antigen content for selected serotypes for phase 3 assessment.
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