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Safety, tolerability and immunogenicity of a novel 24-valent pneumococcal vaccine in toddlers: A phase 1 randomized
Dorota Borys1, Richard Rupp2, Ronald Smulders3
1GSK, Avenue Fleming 20, Wavre 1300, Belgium.
Insights
A new 24-valent pneumococcal vaccine (Pn-MAPS24v) demonstrated an acceptable safety profile in toddlers. The vaccine elicited robust immune responses, supporting further clinical evaluation for broader pneumococcal disease protection.
Area of Science:
- Vaccinology
- Immunology
- Pediatrics
Background:
- Pneumococcal conjugate vaccines (PCVs) have reduced disease burden, but broader serotype coverage is needed.
- A novel 24-valent pneumococcal vaccine (Pn-MAPS24v) utilizing Multiple Antigen-Presenting System (MAPS) technology was developed.
- Assessing the safety, tolerability, and immunogenicity of Pn-MAPS24v in toddlers is crucial for expanding protection against pneumococcal disease.
Purpose of the Study:
- To evaluate the safety, tolerability, and immunogenicity of a 24-valent pneumococcal vaccine (Pn-MAPS24v) in toddlers.
- To compare the Pn-MAPS24v vaccine with the 13-valent pneumococcal conjugate vaccine (PCV13) in terms of reactogenicity and immunogenicity.
- To determine the optimal dose for Pn-MAPS24v based on safety and immune responses.
Main Methods:
- A phase 1, blinded, dose-escalation, active-controlled multicenter study was conducted in 12-15-month-old toddlers.
- Participants received a single dose of Pn-MAPS24v at three dose levels (1 μg, 2 μg, 5 μg) or PCV13.
- Safety assessments included reactogenicity, treatment-emergent adverse events (TEAEs), and serious adverse events (SAEs). Immunogenicity was measured by serotype-specific IgG concentrations and opsonophagocytic activity (OPA) titers.
Main Results:
- The Pn-MAPS24v vaccine demonstrated an acceptable safety profile, with adverse event frequencies similar to PCV13.
- No vaccine-related serious adverse events (SAEs) were reported across all Pn-MAPS24v dose groups.
- Pn-MAPS24v elicited significant IgG and OPA responses to all 13 common serotypes and most of the 11 unique serotypes evaluated.
Conclusions:
- A single dose of Pn-MAPS24v is safe and well-tolerated in toddlers, with dose levels showing similar safety profiles.
- The vaccine induces robust immune responses, including IgG and OPA, against a broad range of pneumococcal serotypes.
- These findings support the further clinical development of Pn-MAPS24v for enhanced pneumococcal disease prevention in infants and toddlers.
Background:
Pneumococcal conjugate vaccines (PCVs) significantly reduced pneumococcal disease burden. Nevertheless, alternative approaches for controlling more serotypes are needed. Here, the safety, tolerability, and immunogenicity of a 24-valent (1/2/3/4/5/6A/6B/7F/8/9N/9V/10A/11A/12F/14/15B/17F/18C/19A/19F/20B/22F/23F/33F) pneumococcal vaccine based on Multiple Antigen-Presenting System (MAPS) technology (Pn-MAPS24v) was assessed in toddlers.
Methods:
In this phase 1, blinded, dose-escalation, active-controlled multicenter study conducted in the United States (September/2020-April/2022), 12-15-month-old toddlers primed with three doses of 13-valent PCV (PCV13) were randomized 3:2 to receive a single dose of one of three Pn-MAPS24v dose levels (1 μg/2 μg/5 μg per polysaccharide) or PCV13 intramuscularly. Reactogenicity (within 7 days), treatment-emergent adverse events (TEAEs, within 180 days), serious/medically attended adverse events (SAEs/MAAEs, within 180 days), and immunogenicity (serotype-specific anti-capsular polysaccharide immunoglobulin G [IgG] and opsonophagocytic activity [OPA] responses at 30 days post-vaccination) were assessed.
Results:
Of 75 toddlers enrolled, 74 completed the study (Pn-MAPS24v 1 μg/2 μg/5 μg: 15/14/16, PCV13: 29). Frequencies of local (60 %/67 %/31 %) and systemic events (67 %/67 %/75 %) in the Pn-MAPS24v 1 μg/2 μg/5 μg and the PCV13 (55 %, 79 %) groups were in similar ranges. TEAEs were reported by 47 %/40 %/63 % of Pn-MAPS24v 1 μg/2 μg/5 μg recipients and 52 % of PCV13 recipients. No vaccine-related SAE was reported. At 30 days post-vaccination, for each of the 13 common serotypes, ≥93 % of participants in each group had IgG concentrations ≥0.35 μg/mL; >92 % had OPA titers ≥lower limit of quantitation (LLOQ), except for serotype 1 (79 %). For 7/11 unique serotypes (2/8/9N/11A/17F/22F/33F), at all dose levels, ≥78 % of Pn-MAPS24v recipients in each group had IgG concentrations ≥0.35 μg/mL and 80 %-100 % had OPA titers ≥LLOQ.
Conclusions:
In 12-15-month-old toddlers, a single dose of Pn-MAPS24v showed an acceptable safety profile, regardless of dose level; AEs were reported at similar frequencies by Pn-MAPS24v and PCV13 recipients. Pn-MAPS24v elicited IgG and OPA responses to all common and most unique serotypes. These results support further clinical evaluation in infants.
