Pfizer, BioNTech Adapt COVID Vax Against Omicron

Pfizer and BioNTech announced data evaluating the safety, tolerability, and immunogenicity of two Omicron-adapted COVID-19 vaccine candidates: one monovalent and the other bivalent, a combination of the Pfizer-BioNTech COVID-19 Vaccine and a vaccine candidate targeting the spike protein of the Omicron BA.1 variant of concern. Data from the Phase 2/3 trial found that a booster dose of both Omicron-adapted vaccine candidates elicited a higher immune response against Omicron BA.1 as compared to the companies’ current COVID-19 vaccine. The immune response was seen across two investigational dose levels, 30 µg and 60 µg.
                                                     
In the Phase 2/3 trial in 1,234 participants 56 years of age and older the pre-specified criterion for superiority was measured by the ratio of neutralizing geometric mean titers (GMR) with the lower bound of the 95% confidence interval >1. The geometric mean ratios (GMRs) for the monovalent 30 µg and 60 µg vaccines compared to the current COVID-19 vaccine were 2.23 (95%) and 3.15 (95%), respectively. The GMRs for the bivalent 30 µg and 60 µg vaccines compared to the current COVID-19 vaccine were 1.56 (95%) and 1.97 (95%), respectively. The monovalent Omicron-adapted vaccine 30 µg and 60 µg achieved a lower bound 95% confidence interval for GMR of >1.5, consistent with the regulatory requirement of superiority. Demonstration of superiority against Omicron and safety are regulatory requirements for potential emergency use authorization of a variant-adapted vaccine.
 
One month after administration, a booster dose of the Omicron-adapted monovalent candidates (30 µg and 60 µg) increased neutralizing geometric mean titers (GMT) against Omicron BA.1 13.5 and 19.6-fold above pre-booster dose levels, while a booster dose of the Omicron-adapted bivalent candidates conferred a 9.1 and 10.9-fold increase in neutralizing GMTs against Omicron BA.1. Both Omicron-adapted vaccine candidates were well-tolerated in participants who received one or the other Omicron-adapted vaccine.
 
In a SARS-CoV-2 live virus neutralization assay tested on sera from participants over 56 years of age and older, sera efficiently neutralized BA.4/BA.5 with titers approximately 3-fold lower than BA.1. Pfizer and BioNTech will continue to collect additional study data on Omicron BA.4/BA.5 over the coming weeks.
 
These results are being shared with the U.S. FDA and European Medicines Agency in advance of upcoming discussions with the FDA Vaccines and Related Biological Products Advisory Committee (VRBPAC) on June 28.