The FDA has trimmed the authorization for monoclonal antibodies made by Eli Lilly and Regeneron as recent data suggests they are not effective against the omicron variant currently driving a wave of COVID-19 infections.
States have been distributing the antibody drugs to treat COVID-19 patients even as omicron became the dominant strain in the U.S. and elsewhere. But data from the companies themselves has suggested the antibodies developed earlier in the pandemic are no longer effective.
In response, the FDA has now revised emergency use authorizations for the Lilly and Regeneron antibodies, limiting their use to patients who have been infected with or exposed to a variant that is susceptible to the treatments.
“Monoclonal antibodies are laboratory-made proteins that mimic the immune system’s ability to fight off harmful pathogens such as viruses, like SARS-CoV-2,” the FDA said in its announcement. “And like other infectious organisms, SARS-CoV-2 can mutate over time, resulting in certain treatments not working against certain variants such as omicron. This is the case with these two treatments for which we’re making changes today.”
Based on CDC data as of Jan. 15, omicron accounted for more than 99% of all new cases in the U.S. That means the Regeneron and Lilly antibodies may be nearing the end of their useful life in their current formulations, as acknowledged by Lilly CEO David Ricks last week at Fierce JPM Week.
"Because data show these treatments are highly unlikely to be active against the omicron variant, which is circulating at a very high frequency throughout the U.S., these treatments are not authorized for use in any U.S. states, territories, and jurisdictions at this time," the FDA said.
The FDA’s action “avoids exposing patients to side effects, such as injection site reactions or allergic reactions, which can be potentially serious, from specific treatment agents that are not expected to provide benefit to patients,” the agency explained in the release.
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Earlier this month, the NIH recommended against the use of Lilly’s cocktail (bamlanivimab and etesevimab) and Regeneron’s treatment REGEN-COV (casirivimab and imdevimab) because of markedly reduced activity against the omicron variant and because real-time testing to identify rare, non-omicron variants is not routinely available.
But the treatments remained in circulation in many states, with nearly 110,000 doses distributed in the second and third weeks of this month according to data from the Department of Health and Human Services.
For example, nearly 13,000 doses of Regeneron's product were used in Florida in the last two weeks. Earlier this month, amid a surge of omicron in his state, Florida Gov. Ron DeSantis criticized the Biden administration for pausing shipments of the antibodies and claimed that the treatments were effective against the variant.
“Omicron is not the only variant that’s out there,” DeSantis said during a Jan. 3 press conference. “And it’s something that we actually have seen applied with omicron patients and we have seen symptoms resolved.”
A COVID-19 antibody treatment produced by GlaxoSmithKline and Vir Biotechnology has been shown to be effective against the omicron variant. But supplies of the drug are in short supply due to overwhelming demand.
Merck and Ridgeback’s antiviral pill molnupiravir and Pfizer’s antiviral Paxlovid also are expected to work against the omicron variant. Merck began supplying the treatment last month. Pfizer expects to do the same in the coming weeks.