Pfizer Inc (PFE)

[DewDiligence]

PFE/BNTX’s monovalent-omicron COVID booster worked better against omicron than PFE/BNTX’s bivalent booster (half omicron and half original); both vaccines were tested at doses of 30mcg and 60mcg. (PFE’s existing booster for adults and adolescents is 30mcg.) All four cohorts (2 vaccines x 2 doses) elicited strong neutralizing-antibody titers against omicron BA.1, but only the monovalent-omicron vaccine was statsig superior to the original booster based on the prespecified metric for superiority, as described below. Neutralizing-antibody titers were 3-fold lower against omicron BA.4/BA.5 than against BA.1, which is not surprising insofar as the omicron boosters are based on BA.1.

https://www.globenewswire.com/news-release/2022/06/25/2469087/0/en/Pfizer-and-BioNTech-Announce-Omicron-Adapted-COVID-19-Vaccine-Candidates-Demonstrate-High-Immune-Response-Against-Omicron.html

The Omicron adapted vaccine candidates (30 mcg and 60 mcg) studied in the Phase 2/3 trial in 1,234 participants 56 years of age and older elicited substantially higher neutralizing antibody responses against Omicron BA.1 when compared to the companies’ current COVID-19 vaccine.

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 mcg and 60 mcg vaccines compared to the current COVID-19 vaccine were 2.23 (95% CI: 1.65, 3.00) and 3.15 (95% CI: 2.38, 4.16), respectively. The GMRs for the bivalent 30 mcg and 60 mcg vaccines compared to the current COVID-19 vaccine were 1.56 (95% CI: 1.17, 2.08) and 1.97 (95% CI: 1.45, 2.68), respectively.

The monovalent Omicron-adapted vaccine 30 mcg and 60 mcg achieved a lower bound 95% confidence interval for GMR of >1.5, consistent with the regulatory requirement of superiority. [The bivalent vaccine apparently was not statsig on the primary endpoint.]

…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.

In short, it looks like the monovalent omicron booster may be the way to go, but this could still change.