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U.S. Department of Health and Human Services

Important Update: May 26, 2021

Monoclonal Antibody Therapeutic Updates

The COVID-19 pandemic is rapidly evolving, and new updates are issued frequently. To view a full list of HHS/ASPR’s updates related to COVID-19 monoclonal antibody therapeutics, please see our full list of updates.


Distribution of Bamlanivimab/etesevimab

Distribution of this product to Illinois, Massachusetts, Arizona, California, Florida, Indiana, Oregon and Washington has been paused. Please see updates below for additional information.

The Assistant Secretary for Preparedness and Response (ASPR) and the Food and Drug Administration (FDA) within the U.S. Department of Health and Human Services are committed to ensuring timely and transparent communication regarding the COVID-19 monoclonal antibody treatments currently authorized for emergency use in certain patients with COVID-19.

The Centers for Disease Control and Prevention (CDC) has identified that the combined frequency of the P.1 variant (first identified in Brazil) and the B.1.351 variant (first identified in South Africa) now exceeds 10% in Arizona, California, Florida, Indiana, Oregon and Washington (https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/variant-proportions.html). Results from in vitro assays that are used to assess the susceptibility of viral variants to particular monoclonal antibodies suggest that bamlanivimab and etesevimab administered together are not active against either the P.1 or B.1.351 variants. These assays use “pseudo-virus particles” that help determine likely susceptibility of the live virus.

REGEN-COV is an alternative monoclonal antibody therapy that is currently authorized for the same use as bamlanivimab and etesevimab administered together and, based on similar in vitro assay data currently available, REGEN-COV is likely to retain activity against the P.1 and B.1.351 variants. All treatment delivery sites can continue ordering REGEN-COV from the authorized distributer by following the existing ordering and reporting procedures.

The FDA recommends that health care providers in Arizona, California, Florida, Indiana, Oregon, and Washington use this alternative authorized monoclonal antibody therapy until further notice. ASPR will pause distribution of bamlanivimab and etesevimab together and etesevimab alone (to pair with existing supply of bamlanivimab at a facility for use under EUA 094) to Arizona, California, Florida, Indiana, Oregon and Washington.

As detailed in our prior communications (May 7 and May 21, 2021), the P.1 variant has also been persistently elevated at a frequency exceeding 10% in Illinois and Massachusetts. The FDA also recommends using REGEN-COV as an alternative monoclonal antibody therapy in these states. The shipping restrictions of bamlanivimab and etesevimab together and etesevimab alone to Illinois and Massachusetts also remain in effect.

Other states, except those noted above, are not impacted by today’s announcement. All health care providers should monitor information from the CDC and state and local health authorities regarding the frequency of the P.1 and B.1.351 variants in their region.

Health care providers should review the Antiviral Resistance information in Section 15 of the authorized Fact Sheets for each monoclonal antibody therapy available under an EUA for details regarding specific variants and resistance. Health care providers should also refer to the CDC website (https://www.cdc.gov/coronavirus/2019-ncov/cases-updates/variant-proportions.html) and information from state and local health authorities regarding reports of viral variants of importance in their region to guide treatment decisions.

Monoclonal antibody therapies available under an EUA must be used in accordance with the terms and conditions for the respective authorization, including the authorized labeling. The Letters of Authorization may be accessed at: https://www.fda.gov/emergency-preparedness-and-response/mcm-legal-regulatory-and-policy-framework/emergency-use-authorization#coviddrugs.

ASPR and FDA will continue to work with the CDC and the National Institutes of Health on surveillance of variants that may impact the use of the monoclonal antibody therapies authorized for emergency use. We will provide further updates and consider additional action as new information becomes available.



  • This page last reviewed: September 15, 2021