Dive Brief:

• Eli Lilly has asked the Food and Drug Administration to remove the emergency authorization for its COVID-19 antibody drug bamlanivimab less than six months after the regulator first cleared it for use in the U.S.

• Lilly made the request due to the “evolving variant landscape” in the U.S. and availability of a superior regimen that combines bamlanivimab with another drug, etesevimab, the drugmaker said in a statement. The move wasn’t a surprise, as the U.S. government stopped distributing Lilly’s single antibody therapy last month over concerns about its effectiveness against certain variants.

• The request is emblematic of the transition in the U.S. to a new phase of the pandemic, in which new infections are being driven by variants gaining traction in the country. Cocktails of COVID-19 antibody drugs like bamlanivimab-etesevimab, which still remain underutilized but have shown they can prevent hospital stays and death from COVID-19, could play a key role in mitigating their impact.

Dive Insight:

Though the development of multiple protective coronavirus vaccines in record time was a remarkable scientific achievement, so too was the work to quickly produce antibody drugs for COVID-19.

Eli Lilly and Regeneron created, tested, and won emergency clearances for similar antibody drugs in less than a year. Since their initial authorizations in November, each of those drugs has definitively shown, in rigorous, placebo-controlled trials, an ability to keep people who are beginning to get sick from COVID-19 — particularly those at high risk of becoming hospitalized — from getting worse.

Recent data has proved antibody drugs can prevent infections in people recently exposed to the virus as well. And Regeneron could soon bring to market a version of its treatment administered through an at-home injection, much more convenient than the cumbersome infusions that have proven a key barrier to use.

Despite these benefits, antibody drugs have been underutilized because of logistical issues, like identifying the patients who need them — and treating them — quickly enough for the drugs to have an impact. It’s unclear whether they’re at all helpful for patients who are already hospitalized. And now they’re being tested in other ways, as the fast evolution of the coronavirus has given rise to variants that may be less susceptible to treatment.

The biggest culprit has been bamlanivimab. The antibody was the first of two that Lilly brought through testing, and the first drug of its kind the FDA cleared for emergency use. But because the drug is a single antibody and can only lock on to the coronavirus in one place, it’s more susceptible to the virus’s evolutionary tricks.

Indeed, while bamlanivimab is helpful against the coronavirus’s original strain as well as a variant that originated in the U.K., clinical research over the past few months has shown the drug to be significantly less potent against other so-called variants of concern.

The U.S. government, as a result, stopped distributing bamlanivimab last month. And now Lilly has taken steps to officially pull it from the market, less than half a year after it first arrived.

Regeneron’s two-drug antibody “cocktail” has proven more effective against variants. Lilly’s version, which combines bamlanivimab with a second antibody called etesevimab and was authorized in February, seems more potent as well. The drugmaker noted in a statement Wednesday that the dual regimen can neutralize more of the emerging variants — including a rapidly expanding strain that originated in California — than bamlanivimab alone.

Lilly is now focusing exclusively on the cocktail and has modified its supply contracts with the U.S. government to ensure all distribution sites have access to both components of the treatment. The company has asked sites stocked with bamlanivimab to order etesevimab rather than dump the drug.

Lilly may develop “complementary neutralizing antibodies,” if necessary, to address variants that could arise in the future, the company said in a statement.

Amgen is helping Lilly manufacture the dual-antibody regimen, and the companies expect to make enough drug, combined, to meet global supply needs.