FDA Panel Suggests Redesigning Vaccines to Target Omicron Variants, Pfizer & Sanofi Share Booster Updates

US FDA advisers voted 19 to 2 in favor of including Omicron-specific components for upcoming COVID-19 booster vaccines on June 28th, the Vaccines and Related Biological Products Advisory Committee deemed new vaccines would offer better protection against the dominant strain and the upcoming autumn surge. 

In light of increased infection rates observed globally, Pfizer BioNTech and GSK Sanofi shared new clinical updates of their new COVID-19 vaccines, both reported to produce high immune responses against Omicron.

Related article: Learning From the COVID-19 Pandemic With Moderna CEO, Stéphane Bancel 

Getting Ahead of Omicron Surge

Currently, Omicron variants BA.4 and BA.5 are the dominant strains in the US. While the FDA panel decided that top-up shots should target the Omicron variant, it did not limit vaccine types, meaning that people in the US could get different vaccines (monovalent or bivalent vaccines). 

This recommendation could pave the way for approval of additional booster shots, eg. a fourth injection for the general Americans, a fifth injection for older or immunocompromised individuals. Drug makers are expected to switch manufacturing operations to make vaccine types that the panel believes will provide better protection, and be the first vaccine design change since 2020.

For the future, the working group is working on centralizing processes for regular COVID-19 boosters if needed, especially on streamlining coordination for clinical studies. 

Pfizer-BioNTech’s Monovalent & Bivalent Candidates Performing Well

The pair released new data on their candidates: one monovalent and the other bivalent vaccines, a combination of the original Pfizer-BioNTech COVID-19 Vaccine (Comirnaty) and a candidate targeting the Omicron BA.1 variant of concern’s spike protein. 

Data from a Phase 1/2 study found a booster dose of both candidates induced a higher immune response against Omicron BA.1 compared to the companies’ current COVID-19 vaccine. 

A month after administration, a booster dose of the monovalent candidates (30 µg & 60 µg) increased neutralizing geometric mean titers (GMT) against Omicron BA.1 by 13.5 and 19.6-fold, a booster dose of the bivalent candidates resulted in a 9.1 and 10.9-fold increase in neutralization against Omicron BA.1.

Related article: Moderna Shares Promising Preliminary Bivalent COVID-19 Booster Results

Sanofi-GSK Claimed First in Omicron Study

Despite being slow in the COVID-19 vaccines race, Sanofi and GSK claimed first in a vaccine efficacy study against Omicron, backed by two trials, VAT02 Cohort 2 and COVIBOOST VAT013, conducted with its new next-generation COVID-19 booster candidate modeled on the Beta variant antigen and including GSK’s pandemic adjuvant.

In the Phase 3 VAT08 trial, of more than 13,000 participants 18 and above years of age, the pair’s vaccine candidate demonstrated efficacy of 64.7% against symptomatic COVID-19 and its efficacy increased to 72% in symptomatic Omicron cases.

While in the independent COVIBOOST (VAT013) study, a Sanofi-GSK booster following initial two doses of the Pfizer-BioNTech’s Comirnaty vaccine produced a higher immune response at 76.1% higher neutralizing antibody titers, compared to the Pfizer BioNTech D614 booster (63.2%).

“These positive data show efficacy of our protein-based, bivalent adjuvanted vaccine candidate in an environment of high Omicron variant circulation. Our vaccine candidate has the potential to make an important contribution to public health as the pandemic evolves further. We are looking forward to the discussions with regulatory authorities with the aim of making our vaccine candidate available later this year,” said Roger Connor, President of GSK Vaccines.

All four companies are submitting their data to the FDA, intending to come to market later this year in preparation for the projected COVID-19 surge.

Author

Fujie Tham