But COVID-19 cases remain elevated following the spread of a series of omicron sublineages, which pose a threat to those vaccinated and naturally infected with various lineages of the coronavirus.
A variety of companies are developing next-generation COVID-19 vaccines that could potentially optimize the strength and durability of immune protection compared to the first crop of vaccines.
Here, we round up notable COVID-19 vaccine candidates that, at least, could help pave the way for the fall 2022 booster drive.
Pfizer Inc. (NYSE:PFE) and BioNTech SE (Nasdaq:BNTX) are developing a bivalent COVID-19 vaccine candidate known as BNT162b5 based on the ancestral strain and a BA.2 omicron variant. The vaccine has a modified spike protein design to optimize the immune response against various COVID-19 variants.
The BNT162b5 vaccine candidate is now in a Phase 2 trial. The U.S. study will enroll approximately 200 participants between the ages of 18 and 55.
The companies recently filed a submission with the European Medicines Agency (EMA) for an Omicron-adapted bivalent COVID-19 vaccine candidate. In addition, the companies announced that the vaccine candidate was based on the BA.1 sub-lineage of omicron. The companies are pursuing authorization for individuals 12 years old and up.
While Pfizer has not selected a final COVID-19 booster candidate for the fall, the company will “likely” be able to deliver an updated vaccine in the early fall, CEO Albert Bourla said in an interview with Barron’s.
Earlier this year, Pfizer and BioNTech announced they were developing a bivalent omicron-adapted vaccine that is now in clinical trials. The vaccine encodes both the ancestral SARS-CoV-2 spike protein and the spike protein for the omicron BA.1 variant. The companies have already shared data from a Phase 2/3 study of BNT162b2.
A dose of Moderna’s (Nasdaq:MRNA) mRNA-1273.222 bivalent booster candidate combines 25 µg of omicron BA.4/5 mRNA and 25 µg of its FDA-approved Spikevax COVID-19 vaccine. The company is developing the vaccine based on recent FDA feedback.
Moderna’s bivalent vaccine mRNA-1273.214 is based on the original SARS-CoV-2 virus and the first omicron version. It outperformed the company’s original vaccine in a June 2022 analysis, offering significantly higher omicron neutralizing titers when administered as a fourth dose compared to its original vaccine, mRNA-1273.
The mRNA-1273.214 booster is “the only candidate expected to have demonstrated significantly higher titers against the BA.4/5 strain in a clinical trial [compared to a currently authorized booster] before the fall booster season,” Moderna explained in a press release.
Moderna also noted that a fourth dose of mRNA-1273.214 yielded similar local reactogenicity to the second and third doses of mRNA-1273 vaccine. According to a presentation shared with FDA, a dose of mRNA-1273.214 bolstered protection against omicron BA.4/BA.5 one month after administration in recipients who had received three initial doses of mRNA-1273.
In a July press release, Moderna indicated that some countries have expressed a preference for the mRNA-1273.214 vaccine candidate over the mRNA-1273.222 version.
Moderna’s (Nasdaq:MRNA) omicron-based vaccine candidate mRNA-1273.529 is now the focus of a Phase 2 study. With the FDA, however, backing a bivalent booster vaccine design, mRNA-1273.529 is more likely to provide content to the study of mRNA-1273.214, a vaccine with a bivalent design targeting the first version of omicron and the original virus.
Sanofi-GSK next-generation COVID-19 booster
Based on the beta variant, the Sanofi-GSK COVID-19 booster candidate offered a significant boost in antibody titers against the omicron BA.1 lineage. The companies also noted that, in the independent COVIBOOST (VAT013) study, the booster candidate yielded a superior immune response than the first-generation Pfizer-BioNTech vaccine booster. The companies’ first-generation vaccine stalled in late 2020 after it failed to generate a sufficient immune response in recipients over 50.
Filed Under: Infectious Disease