Jan. 25, 2022 -- The FDA has revised its emergency use authorization (EUA) for two monoclonal antibody combinations to treat mild-to-moderate COVID-19 because they are not effective against the dominant Omicron variant.

The drugs are bamlanivimab combined with etesevimab from Eli Lilly, which was authorized for use in February 2021, and casirivimab with imdevimab, from Regeneron, which received an EUA in November 2020.

The FDA action is in line with the National Institutes of Health (NIH) COVID-19 Treatment Guidelines Panel, which recently advised against use of the drugs due to reduced activity against Omicron and because real-time testing to identify rare, non-Omicron variants is not readily available.

“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 United States, these treatments are not authorized for use in any U.S. states, territories, and jurisdictions at this time,” Patrizia Cavazzoni, MD, director of the FDA’s Center for Drug Evaluation and Research, said in a statement.

Revising these EUAs “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 who have been infected with or exposed to the omicron variant,” she added.

The FDA said if data shows the drugs are again effective against circulating coronavirus, they could be authorized for use again.

The Department of Health and Human Services is halting distribution of these specific monoclonal antibodies to the states, according toThe Washington Post.

AMA on Board

The American Medical Association supports the FDA decision.

 “Given the latest data showing the Omicron variant of SARS-CoV-2 is responsible for 99% of current COVID-19 infections, we are pleased that the FDA is following the scientific evidence and limiting the use of monoclonal antibody treatments to those that are effective against the Omicron variant,” AMA President Gerald E. Harmon, MD, said in a statement,

“Importantly,” said the FDA's Cavazzoni, there are several other drugs that are expected to be effective against Omicron. They include two antiviral pills granted authorization last month: ritonavir plus nirmatrelvir (from Pfizer) and molnupiravir (from Merck).

Sotrovimab from GlaxoSmithKline and remdesivir, from Gilead Sciences, are also expected to work against Omicron.