FDA pulls Evusheld authorization as coronavirus evolution quashes another therapy

The evolution of the coronavirus has knocked out another treatment.

The Food and Drug Administration on Thursday withdrew the authorization of Evusheld, the latest antibody therapy to be rendered ineffective by the mutations the virus has picked up. Notably, Evusheld — unlike other antibody therapies — was not for infected patients, but rather was given as a pre-exposure treatment to people at high risk for severe Covid-19, such as those with compromised immune systems.

The end of Evusheld, made by AstraZeneca, is not unexpected. The FDA warned in October that emerging forms of the Omicron variant were undermining the power of the therapy. Earlier this month, the agency said that it anticipated that Evusheld would not neutralize the now-dominant XBB.1.5 Omicron sublineage, but that it was awaiting further data.

Still, the withdrawal amounts to another blow to the nation’s toolkit for fighting the coronavirus. People with certain health conditions have trouble mounting their own immune responses to vaccines, so they turned to Evusheld as a way to protect themselves against getting Covid-19.

The FDA’s announcement Thursday indicated that Evusheld lost its authorization because sublineages that aren’t neutralized by the therapy are causing at least 90% of infections now. But the agency said that clinics with stores of the treatment should hold onto them, should variants that are susceptible to Evusheld emerge in the future.

In a statement, AstraZeneca said it has started trials of another antibody that, in lab studies so far, has been able to neutralize all variants. The therapy, which would similarly be given as a pre-exposure prophylaxis to immunocompromised people, could be available later this year if trials are successful, the company said.

The company’s statement also noted that Evusheld remains authorized in other countries, including the European Union and Japan.

Beyond Evusheld, the virus’s evolution has also left the country without any antibody therapies for patients once they’re infected. The last of the treatments, bebtelovimab, lost its authorization in November.

The oral antiviral Paxlovid from Pfizer continues to be available, but many people — including transplant recipients — are on medications that can’t be taken at the same time as Paxlovid.

Other treatments include another oral antiviral, Merck’s molnupiravir, but it is not as effective as Paxlovid. Remdesivir, or Veklury, from Gilead, helps prevent severe disease in infected patients, but it has to be given intravenously over three days, presenting a major obstacle versus an oral treatment.

Antibody developers, meanwhile, say they are working on next-generation treatments that could stand up to additional evolution in the SARS-CoV-2 virus, and have been urging regulators to adopt more flexibility in authorizing the next round of therapies. As of now, however, no new antibody therapy appears close to becoming available.

Overall, the country’s Covid situation appears to be easing for now. While the daily average number of people hospitalized who tested positive for the coronavirus had been on the rise since November and earlier this month neared 50,000 — surpassing last summer’s bump — it’s since fallen to about 35,000. Average daily deaths, however, which had been hovering in the 300s in the fall, have risen into the 500s and have yet to drop.

Crucially, the wave the country experienced in the past few months was much smaller in terms of hospitalizations and deaths than those in the winters of 2020-2021 and 2021-2022, as well as the Delta wave. The immunity people have built up from vaccinations and infections continues to protect most from severe outcomes.

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