The US health regulator revised on Monday (Jan 24) the emergency use authorizations for Covid-19 antibody treatments from Regeneron and Eli Lilly to limit their use, as the drugs are unlikely to work against the Omicron coronavirus variant.
The Food and Drug Administration (FDA) said the treatments are currently not cleared for use in any US states or territories, but may be authorised in certain regions if they work against potential new variants.
The agency highlighted other therapies that are expected to be effective against Omicron, including a rival antibody drug from GlaxoSmithKline and Vir Biotechnology as well as recently authorised antiviral pills from Pfizer and Merck & Co.
Last month, the US government had paused the distribution of Regeneron and Lilly's treatments and said the halt would continue until new data emerges on their efficacy against Omicron.
The highly contagious new variant was estimated to account for more than 99 per cent of cases in the United States, as of Jan 15.
GSK and Vir Biotech are boosting production of their drug, sotrovimab, to help meet soaring demand in the United States.
The FDA has also expanded its approval for the use of Gilead Sciences' antiviral Covid-19 drug remdesivir to treat non-hospitalised patients aged 12 years and above. read more
The Washington Post earlier in the day reported that the FDA was expected to revise authorizations for Regeneron and Lilly's treatments.
Regeneron said it is working with the FDA to bring additional monoclonal antibody treatments to patients.
"Pending regulatory discussions, new therapeutic candidates could enter the clinic in coming months," the company said in a statement.
Lilly had no immediate comment but pointed to its statement from December saying its antibody candidate, bebtelovimab, maintains neutralization activity against all known variants of concern, including Omicron.