Pfizer and BioNTech moved a step closer to a planned Covid-19 boost campaign this fall by completion their request for emergency approval from the FDA for a version of their messenger RNA injection adapted to the predominant omicron subvariants circulating in the US. The companies said Monday that once approval is granted, the booster shots will be available to ship immediately.
The booster vaccine is a bivalent vaccine designed from two main parts: one that protects against the original SARS-CoV-2 virus and the other that targets the now dominant omicron subvariants BA.4 and BA.5. But in seeking approval for this booster vaccine, Pfizer and BioNTech are moving forward without the same level of data that supported approval of the original vaccine.
The only booster clinical data that Pfizer and BioNTech have is for a version of the vaccine that protects against the original strain and the BA.1 omicron subvariant. In a phase 2/3 study testing a dose of 30 micrograms, the companies reported in June that this shot elicited a better immune response against the BA.1 variant than the version of the vaccine designed for the original strain. Based in part on these results, an FDA advisory committee then voted to recommend that the omicron component be part of new booster shots.
After the FDA committee’s vote manual issued advising all Covid-19 vaccine manufacturers to modify their boosters to handle the BA.4 and BA.5 subvariants that have become the dominant strains in the U.S. At the time, Peter Marks, director of the Evaluation Center, said and FDA Biologics Research that clinical data for BA.1 would be sufficient to request approval for booster injections targeting the BA.4 and BA.5 subvariants.
Pfizer and BioNTech only have preclinical data testing their booster against the BA.4 and BA.5 subvariants. In these results, the companies report that the shot generated a strong neutralizing antibody response against four omicron subvariants as well as the original strain. A clinical trial testing this updated vaccine in people 12 and older is on track to begin by the end of August.
The suggested dosing schedule is a single booster vaccine for those who have completed the primary vaccination series with any approved or authorized Covid-19 vaccine. The companies are also seeking approval for a second booster dose in people age 50 and older, as well as those 12 and older with compromised immune systems.
“Having rapidly ramped up production, we are able to immediately begin distribution of the Omicron BA.4/BA.5 bivalent boosters, if authorized, to help protect individuals and families as we prepare for potential fall and winter surges Pfizer Chairman and CEO Albert Burla said in a prepared statement.
The federal government reached a $3.2 billion deal with Pfizer in June covering purchase of 105 million doses of the booster shots. The government also has the option to purchase up to 195 million additional doses. Last month the government signed a $1.74 billion purchase agreement with Moderna for its bivalent booster injection. This deal covers the government’s purchase of 66 million doses with an option to purchase up to 234 million more doses.
Pfizer and BioNTech are also seeking approval for their booster injection in Europe. They said on Monday that the application for a conditional marketing authorization with the European Medicines Agency is expected to be completed in the coming days.
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