Pfizer Inc. and BioNTech SE announced results from a Phase 2/3 trial showing a favorable safety profile and robust neutralizing antibody responses in children 5 to 11 years of age using a two-dose regimen of 10 µg administered 21 days apart, a smaller dose than the 30 µg dose used for people 12 and older.
The antibody responses in the participants given 10 µg doses were comparable to those recorded in a previous Pfizer-BioNTech study in people 16 to 25 years of age immunized with 30 µg doses. The 10 µg dose was carefully selected as the preferred dose for safety, tolerability and immunogenicity in children 5 to 11 years of age. These are the first results from a pivotal trial of a COVID-19 vaccine in this age group.
The data summarized from this Phase 2/3 study, which is enrolling children 6 months to 11 years of age, was for 2,268 participants who were 5 to 11 years of age and received a 10 µg dose level in a two-dose regimen. In the trial, the SARS-CoV-2–neutralizing antibody geometric mean titer (GMT) was 1,197.6 (95% confidence interval), demonstrating strong immune response in this cohort of children one month after the second dose.
This compares well (was non-inferior) to the GMT of 1146.5 from participants ages 16 to 25 years old, used as the control group for this analysis and who were administered a two-dose regimen of 30 µg. Further, the COVID-19 vaccine was well tolerated, with side effects generally comparable to those observed in participants 16 to 25 years of age.
Pfizer and BioNTech plan to share these data with the U.S. Food and Drug Administration (FDA), European Medicines Agency (EMA) and other regulators as soon as possible. For the United States, the companies expect to include the data in a near-term submission for Emergency Use Authorization (EUA) as they continue to accumulate the safety and efficacy data required to file for full FDA approval in this age group. A request to the EMA to update the EU Conditional Marketing Authorization is also planned. Topline readouts for the other two age cohorts from the trial – children 2-5 years of age and children 6 months to 2 years of age – are expected as soon as the fourth quarter of this year.
The Phase 1/2/3 trial initially enrolled up to 4,500 children ages 6 months to 11 years of age in the United States, Finland, Poland and Spain from more than 90 clinical trial sites. It was designed to evaluate the safety, tolerability and immunogenicity of the Pfizer-BioNTech vaccine on a two-dose schedule (approximately 21 days apart) in three age groups: ages 5 to 11 years; ages 2 to 5 years; and ages 6 months to 2 years.
Based on the Phase 1 dose-escalation portion of the trial, children ages 5 to 11 years received two-dose schedule of 10 µg each while children under age 5 received a lower 3 µg dose for each injection in the Phase 2/3 study. The trial enrolled children with or without prior evidence of SARS-CoV-2 infection.
COMIRNATY, which is based on BioNTech’s proprietary mRNA technology, was developed by both BioNTech and Pfizer. BioNTech is the Marketing Authorization Holder in the United States, the European Union, the United Kingdom, Canada and the holder of emergency use authorizations or equivalents in the United States (jointly with Pfizer) and other countries.
