Pfizer: Pfizer Announces Positive Top-Line Results from Phase 3 Study of 20-Valent Pneumococcal Conjugate Vaccine in Infants

Pfizer Inc. (NYSE:PFE) today announced positive top-line results from its pivotal U.S. Phase 3 study (NCT04382326) in infants evaluating its 20-valent pneumococcal conjugate vaccine candidate (20vPnC) for the prevention of invasive pneumococcal disease (IPD) caused by the 20 Streptococcus pneumoniae (pneumococcus) serotypes contained in the vaccine for the pediatric population.

The study had two co-primary objectives, associated with immunogenicity responses one month after the third and fourth doses of the four-dose vaccination series, respectively: non-inferiority (NI) of the percentage of participants with predefined serotype-specific immunoglobin G (IgG) concentrations after Dose 3 and NI of IgG geometric mean concentrations (GMCs) after Dose 4. All 20 serotypes met the co-primary objective of NI of IgG GMCs after Dose 4. Fourteen of the 20 serotypes met the co-primary objective of NI of the percentage of participants with predefined IgG levels after Dose 3 (two serotypes missed by a wider margin while four narrowly missed), and all serotypes met noninferiority for the key secondary objective of IgG GMCs after Dose 3. All 20 serotypes elicited robust functional responses (OPA) and increases in antibody responses after Dose 4, with the totality of data supporting the potential benefit of all serotypes in this 20-valent vaccine candidate.

“We are encouraged by today’s data which show that if approved for a pediatric indication, 20vPnC would have the potential to cover more of the clinically significant remaining burden of infant pneumococcal disease than any other available pneumococcal conjugate vaccine,” said Annaliesa Anderson, Ph.D., Senior Vice President and Chief Scientific Officer, Vaccine Research and Development, Pfizer. “We are grateful to everyone who made this study possible, including the study investigators and in particular the trial participants and their parents/guardians for their contribution to this important research.”

Overall, the safety profile of the 20vPnC candidate was consistent with Prevnar 13 given in the same schedule. A similar percentage of infants receiving either vaccine experienced local reactions (pain at the injection site, redness, and swelling), fever, and other systemic events (decreased appetite, drowsiness, and irritability). The study also met non-inferiority objectives for responses to co-administered routinely used pediatric vaccines.

Based on the totality of positive safety and immunogenicity data, Pfizer plans to submit a supplemental Biologics License Application (sBLA) by the end of this year, subject to discussions with the U.S. Food and Drug Administration. Pfizer will seek to present and publish outcomes from this clinical trial at a future date once safety and immunogenicity data have been fully analyzed. Additional top-line results from other pediatric 20vPnC clinical trials are expected to read out in the second half of 2022, with discussions with other regulatory bodies planned once those pivotal data become available.

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