FDA Halts Use of Some COVID Monoclonal Antibodies Due to Omicron

Megan Brooks

January 25, 2022

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

The US Food and Drug Administration (FDA) has revised the emergency use authorization (EUA) for two monoclonal antibody combinations to treat mild to moderate COVID-19, halting their use, for now, because they are not effective against the dominant Omicron variant.

They are bamlanivimab combined with etesevimab (Eli Lilly), which received an EUA in February 2021, and casirivimab with imdevimab (REGEN-COV, 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 monoclonal antibody combos 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 US 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.

"In the future, if patients in certain geographic regions are likely to be infected or exposed to a variant that is susceptible to these treatments, then use of these treatments may be authorized in these regions," Cavazzoni said.

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

AMA on Board

The American Medical Association (AMA) supports the FDA decision to revise the EUA for these monoclonal antibody cocktails.

"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.

"Limiting the use of these treatments will help ensure patients receive the best available therapy," Harmon said.

"Importantly," said the FDA's Cavazzoni, several other therapies are expected to be effective against Omicron. They include two antiviral pills granted EUA last month: ritonavir plus nirmatrelvir (Paxlovid) and molnupiravir (Lagevrio).

Sotrovimab (GlaxoSmithKline/Vir Biotechnology) and remdesivir (Veklury) are also expected to work against Omicron.

Vaccination and Boosters Key

"Healthcare providers should consult the NIH panel's COVID-19 treatment guidelines and assess whether these treatments are right for their patients," Cavazzoni said.

"While it's critical that we have ways to treat those who contract COVID-19, the authorized treatments are not a substitute for vaccination in individuals for whom COVID-19 vaccination and a booster dose are recommended," she said.

"Data has clearly demonstrated that the available, safe, and effective vaccines can lower your risk of developing COVID-19 and experiencing the potential associated serious disease progression, including hospitalization and death," Cavazzoni said.

Harmon agrees, saying the AMA continues to "strongly urge every eligible individual to make sure they are up to date on their COVID-19 vaccinations, including booster doses.

"The Omicron variant is highly contagious, and the unvaccinated remain most at risk of severe illness, hospitalization, and death if infected. Data further suggests that a booster dose provides greater protection against the Omicron variant," he said.

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