16 - A Randomized Phase 1 Study of a Novel Pneumococcal Conjugate Vaccine in Healthy Japanese Adults in the United States

Background: Because of the number and variability of serotypes causing pneumococcal disease among different geographic regions, age groups, and environmental backgrounds, expanding serotype coverage with pneumococcal conjugate vaccines (PCVs) is a continued unmet need.

Methods: This phase 1, randomized, double-blind study included healthy Japanese adults aged 18–49 years residing in the United States. Subjects were randomized 1:1:1 to receive a single dose of a 20-valent PCV (containing 13-valent PCV [PCV13] serotypes plus 8, 10A, 11A, 12F, 15B, 22F, 33F), a novel pneumococcal polysaccharide conjugate vaccine with extended coverage,  or PCV13 (control). Safety was the primary endpoint and included reactogenicity events occurring ≤ 14 days after vaccination, adverse events (AEs) ≤ 1 month after vaccination, and serious AEs (SAEs) ≤ 6 months after vaccination. The secondary endpoint was pneumococcal serotype-specific immunogenicity as determined by opsonophagocytic activity (OPA) titers on sera collected before and 1 month after vaccination.

Results: Overall, 35 subjects received PCV20 and 35 subjects received PCV13. One subject withdrew before the 1-month follow-up. Local reactions and systemic events across groups were generally mild or moderate (Figure 1). Two vaccine-related AEs occurred (injection site erythema and swelling in the PCV20 group); no severe AEs, SAEs, or safety-related withdrawals were reported. OPA geometric mean titers increased for all 20 serotypes in the PCV20 group and all 13 serotypes in the PCV13 group 1 month after vaccination; corresponding OPA geometric mean fold rises from baseline to 1 month after vaccination are reported (Figure 2; Figure 3).Figure 1
Figure 2
Figure 3


Conclusion: PCV20 was well tolerated and induced serotype-specific functional OPA immune responses that are anticipated to be associated with protection in Japanese adults. ClinicalTrials.gov: NCT03642847.

Funding: Pfizer Inc.