Pfizer announces positive results from phase-III study in 20-valent Pneumococcal Conjugate Vaccine in infants in EU

Pfizer recently announced positive top-line results from its pivotal EU phase-III study in infants (NCT04546425) evaluating its 20-valent pneumococcal conjugate vaccine candidate (20vPnC) for the prevention of invasive pneumococcal disease (IPD), pneumonia and acute otitis media caused by the 20 Streptococcus pneumoniae (pneumococcus) serotypes contained in the vaccine for the pediatric population.

The study had three coprimary outcomes, associated with immunogenicity responses one month after the second and third doses of a three-dose vaccination series given at approximately two, four and 11-12 months of age of 20vPnC compared to Prevenar 13. For the Non-Inferiority (NI) co-primary objective of immunoglobulin G (IgG) geometric mean concentrations (GMCs) one month after dose three at 11-12 months of age, 19 of the 20 serotypes met the NI criteria with only one serotype narrowly missing. For the NI co-primary objective of IgG GMCs one month after dose two, 16 of the 20 serotypes met NI. Finally, for the third NI co-primary objective of the percentage of participants with predefined serotype-specific IgG concentrations one month after dose two, nine of the 20 serotypes met the NI criteria. All 20 serotypes showed increased booster responses from post dose two to post dose three which are indicative of immunological memory and long-term protection. All 20 vaccine serotypes also showed strong functional antibody responses as measured by the opsonophagocytic assay (OPA) post-dose two and post dose three similar to Prevenar and Prevenar 13. The totality of data is, therefore, directionally consistent with prior clinical experience with Prevenar and Prevenar 13 after two and three infant doses, both of which have demonstrated effectiveness in a three-dose schedule against the serotypes contained in the vaccine in post-licensure studies, a statement from Pfizer said.

In summary, the totality of these positive 20vPnC data, combined with the experience with Prevenar 13 in this schedule, demonstrates that the 20vPnC candidate, if approved, is likely to help protect against all 20 vaccine serotypes in a three-dose vaccine series, it further said.

Pfizer plans to file these data by the end of this year with the European Medicines Agency (EMA). These positive data mark the conclusion of pivotal topline readouts for the 20vPnC paediatric programme. The company will also seek to present and publish outcomes from this clinical trial at a future date once safety and immunogenicity data have been fully analysed, the statement concluded.