The Assistant Secretary for Preparedness and Response (ASPR) and the Food and Drug Administration (FDA) have announced that circulating SARS-CoV-2 viral variants, including Omicron, may be associated with resistance to bamlanivimab plus etesevimab or REGEN-COV (casirivimab and imdevimab).

Current data suggests that coadministration of bamlanivimab and etesevimab or REGEN-COV were unlikely to retain activity against the Omicron variant. Based on similar cell structure data available, sotrovimab appears to retain activity against the Omicron variant. The FDA has updated the Fact Sheets for Health Care Providers for bamlanivimab plus etesevimab, REGEN-COV, and sotrovimab with specific information regarding expected activity against the Omicron variant (B.1.1.529/BA.1).

The ASPR will pause further distribution of bamlanivimab plus etesevimab, etesevimab alone, and REGEN-COV pending updated data from the Centers for Disease Control and Prevention (CDC). Shipments of sotrovimab has resumed and delivery of 55,000 doses of product has begun. In January, an additional 300,000 doses of sotrovimab will be available. 

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The use of existing site supply of bamlanivimab plus etesevimab and REGEN-COV may be clinically appropriate in certain geographic regions and health care facilities with a lower frequency of Omicron and limited supply of alternative treatment options. The ASPR and FDA will be providing updated information and recommendations to health care providers allowing them to administer optimal care to patients.

Bamlanivimab plus etesevimab, REGEN-COV, and sotrovimab are currently authorized for emergency use by the FDA for the treatment of mild to moderate COVID-19 in individuals with positive results of direct SARS-CoV-2 viral testing, and who are at high risk for progressing to severe COVID-19, including hospitalization or death. Bamlanivimab plus etesevimab and REGEN-COV are also authorized for post-exposure prophylaxis of COVID-19 in individuals who are at high risk of progression to severe COVID-19, including hospitalization or death.


ASPR pauses allocation of bamlanivimab and etesevimab together, etesevimab alone, and REGEN-COV. News release. US Department of Health and Human Services. December 23, 2021. Accessed December 27, 2021.

This article originally appeared on MPR