Dive Brief:

• The U.S. government is no longer distributing Eli Lilly’s single antibody therapy for COVID-19 because it’s not effective against variants gaining traction in the country, health officials announced Wednesday.

• The drug, bamlanivimab, can still work if used in combination with another Lilly antibody called etesevimab, according to the U.S. Assistant Secretary for Preparedness and Response. The Food and Drug Administration in February cleared this combination for emergency use in recently diagnosed patients at high risk for COVID-19 complications.

• Health facilities that have stockpiles of bamlanivimab can order supplies of etesevimab alone to pair with the single antibody, and all sites can continue to order the combination, ASPR said.

Dive Insight:

U.S. officials are trying to stay ahead of coronavirus variants that are making up an increasing share of infections in the country. Combination antibody treatments, made by Regeneron as well as Lilly, attack the virus in different ways and are designed to better neutralize the threat of viral mutations.

“Lilly developed bamlanivimab and etesevimab for administration together to be prepared for the spread of SARS-CoV-2 variants that could resist treatment with either monoclonal antibody alone,” Lilly said. The company added that it’s working with Amgen to manufacture as many as 1 million doses of etesevimab for use in combination with bamlanivimab by mid-2021.

Studies have shown the antibody treatments can be lifesavers. Just this week, Regeneron released data showing its antibody cocktail could reduce the risk of hospitalization or death in recently diagnosed patients by 70%.

A recent Lilly study also found the combination of bamlanivimab and etesevimab could reduce the risk of hospitalization or death by 87%.

A lingering question, though, revolves around how well the treatments will work as different variants gain traction in the U.S. The Centers for Disease Control and Prevention estimates variants of concern, which made up only a small portion of viral samples tested in early January, had reached about 40% as of March 13.

The FDA recently issued new information to healthcare providers that assessed how susceptible variants originating in the U.K., South Africa, Brazil, California and New York were to the three antibody therapies cleared for use. Lilly’s single antibody treatment retained its potency against the variant from the U.K., dubbed B.1.1.7, but the other variants were all significantly less susceptibleto treatment.

Lilly’s combination therapy fared better, while the Regeneron cocktail maintained its potency against all of the strains, according to the FDA.

The CDC now considers five different strains to be “variants of concern,” including two first detected in California. Health officials are considering adding B.1.526, which is circulating widely in New York, to that list, CDC Director Rochelle Walensky told reporters on Wednesday.