Standard drugs used to fight COVID-19 may not work against Omicron: U.S. doctors

The shrinking toolbox of treatments is a painful reminder that COVID-19 still has the upper hand in the U.S., even with more than 200 million Americans fully vaccinated.

As strained U.S. hospitals brace for a new surge of COVID-19 cases caused by the fast-spreading omicron variant, doctors are warning of yet another challenge: the two standard drugs they’ve used to fight infections are unlikely to work against the new strain.

For more than a year antibody drugs from Regeneron and Eli Lilly have been the go-to treatments for early COVID-19, thanks to their ability to head off severe disease and keep patients out of the hospital.

But both drugmakers recently warned that laboratory testing suggests their therapies will be much less potent against omicron, which contains dozens of mutations that make it harder for antibodies to attack the virus. And while the companies say they can quickly develop new omicron-targeting antibodies, those aren’t expected to launch for at least several months.

A third antibody from British drugmaker GlaxoSmithKline appears to be the best positioned to fight omicron. But Glaxo’s drug is not widely available in the U.S., accounting for a small portion of the millions of doses purchased and distributed by the federal government. U.S. health officials are now rationing scarce drug supplies to states.

“I think there’s going to be a shortage,” said Dr. Jonathan Li, director of the Harvard/Brigham Virology Specialty Laboratory. “We’re down to one FDA-authorized monoclonal antibody” with omicron because of the reduced effectiveness of Regeneron and Lilly’s drugs.

The delta variant still accounts for more than 95% of estimated U.S. cases, according to the Centers for Disease Control and Prevention. But agency leaders say omicron is spreading faster than any past variant and will become the dominant strain nationwide within weeks.

Delivered by injection or infusion, antibodies are laboratory-made versions of human proteins that help the immune system fight off viruses and other infections.

Glaxo’s drug, developed with Vir Biotechnology, was specifically formulated to bind to a part of the virus that is less likely to mutate, according to the companies. Early studies of laboratory-simulated omicron by the drugmakers and outside researchers show promising results.