Pfizer 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.
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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.
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.
In 2020, Pfizer initiated the Phase 3 clinical trial program for the pediatric indication for 20vPnC. Four core Phase 3 pediatric studies will help expand the data on the safety, tolerability, and immunogenicity of 20vPnC.
These studies collectively enrolled approximately 4,700 infants and 800 toddlers and children of all ages including:
• A Phase 3 study describing the tolerability and safety and comparing immunogenicity of 20vPnC to Prevnar 13 in infants vaccinated at 2, 4, 6, and 12-15 months of age in the U.S. (NCT04382326)
• A Phase 3 study describing the tolerability and safety of 20vPnC, with Prevnar 13 serving as the control in infants vaccinated at 2, 4, 6, and 12-15 months of age in multiple countries. (NCT04379713)
• A Phase 3 study describing the tolerability and safety and comparing immunogenicity of 20vPnC to Prevnar 13 in infant vaccination at approximately 2, 4, and 11-12 months of age in Europe and Australia (NCT04546425)
• A Phase 3 study in children 15 months through <18 years of age receiving a single dose of 20vPnC in the U.S. (NCT04642079).
On August 14, 2020, Pfizer’s 20vPnC received the FDA’s Breakthrough Therapy Designation for the prevention of disease caused by Streptococcus pneumoniae serotypes in the vaccine in infants, children, and adolescents.
The FDA previously granted Fast Track Designation for 20vPnC in May 2017 for the pediatric indication.
On June 8, 2021, the FDA approved PREVNAR 20 for the prevention of invasive disease and pneumonia caused by the 20 Streptococcus pneumoniae (pneumococcus) serotypes in the vaccine in adults ages 18 years and older. ■