Phase 2 trial to evaluate the safety and immunogenicity of a 25-valent pneumococcal conjugate vaccine (IVT-PCV25) in infants.
Lulu Bravo, Nancy Bermal, Edison Alberto et al.
✦ AI-curated · Sources linked
In 30 seconds
This double-blind, randomised phase 2 trial in 421 healthy infants in the Philippines compared three dose-ranging formulations of the 25-valent pneumococcal conjugate vaccine IVT-PCV25 with licensed Prevnar-20. Three doses were given four weeks apart from six weeks of age, alongside routine vaccinations, with safety and antibody responses assessed through 28 days after dose three. IVT-PCV25 had an acceptable safety profile, with no serious adverse event attributed to it. Antibody results suggested responses across all 25 serotypes, although the authors noted that formulation optimisation may be needed.
Key findings
- Solicited local and systemic adverse events occurred in 90–93% and 94–99% of IVT-PCV25 recipients, respectively, and were predominantly mild or moderate and transient.
- No serious adverse event was attributed to IVT-PCV25.
- IgG GMTs for 19/25 serotypes exceeded 0.35 μg/mL; for the remaining 6/25, OPA GMTs were > 50-fold the lower limit of quantification.
- A 2-fold change in antigen quantity produced a corresponding 2-fold antibody response for only four serotypes, and by OPA only.
Why it matters
A vaccine covering more pneumococcal serotypes could potentially broaden protection in infants, while the trial’s safety findings support further evaluation of IVT-PCV25. The variable antibody responses across serotypes also highlight that overall valency alone may not ensure balanced immunogenicity; antigen quantities may need refinement before efficacy and broader clinical value can be established.
What to keep in mind
Follow-up for safety and antibody responses extended only to 28 days after dose three. OPA titres were measured in only a third of participants, and the study assessed immunogenicity rather than clinical protection.