The FDA has removed two monoclonal antibody therapies — Eli Lilly’s bamlanivimab + etesevimab and Regeneron’s casirivimab + imdevimab (Regen-Cov) — from its list of emergency authorized COVID-19 treatments due to their ineffectiveness against the Omicron variant, an agency alert reports.

“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,” according to an FDA statement by Patrizia Cavazzoni, MD, director of the FDA’s Center for Drug Evaluation and Research.

The CDC reports the omicron variant of SARS-CoV-2 is estimated to account for more than 99% of cases in the United States as of January 15. The FDA says that it’s “highly unlikely” that COVID-19 patients are infected with a variant other than omicron, and these monoclonal antibody treatments are not authorized to be used at this time.

The FDA says this 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.    

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. 

The FDA notes that there are several other therapies — Paxlovid, sotrovimab, Veklury (remdesivir), and molnupiravir — that are expected to work against the omicron variant, and that are authorized or approved to treat patients with mild-to-moderate COVID-19 who are at high risk for progression to severe disease, including hospitalization or death.

“Healthcare providers should consult the NIH panel’s COVID-19 treatment guidelines and assess whether these treatments are right for their patients,” Cavazzoni said in the FDA alert.

Monoclonal Antibody