GlaxoSmithKline, Vir snag FDA authorization for new COVID-19 antibody. But how will they sell it without a supply deal?

Following in the footsteps of Eli Lilly and Regeneron, a partnership between GlaxoSmithKline and Vir Biotechnology has won an emergency FDA nod for a COVID-19 antibody drug. The difference? It doesn’t have a supply deal with the U.S. government.

Wednesday, the FDA issued (PDF) an emergency use authorization to GSK and Vir’s sotrovimab for mild-to-moderate COVID-19. Same as the previous go-aheads for similar therapies from Lilly and Regeneron, the new nod is limited to patients who aren’t hospitalized but are at high risk of progressing to severe disease.

The anti-coronavirus antibody proved its worth in a phase 3 trial. The Comet-Ice study stopped early after an interim analysis found sotrovimab reduced the number of patients who died or needed hospitalization by 85% over placebo.

The two companies are now evaluating the trial data and plan to file the drug for a full FDA approval in the second half of the year. Last week, the pair got backing from drug reviewers at the European Medicines Agency, opening up potential emergency adoptions in EU member states ahead of a formal green light.

Despite the strong trial showing, the drug’s commercial value remains in question. The new go-ahead comes as roughly 40% of the U.S. population has been fully vaccinated and as earlier-to-market antibody cocktails by Regeneron and Lilly reportedly go unused because of low demand.

RELATED: Vir, GSK COVID-19 antibody slashes hospitalizations and deaths in phase 3, spurring FDA filing plans

Still, Adrienne Shapiro, M.D., Ph.D., of Fred Hutchinson Cancer Research Center, an investigator in the Comet-Ice trial, believes having additional options is necessary. “While preventive measures, including vaccines, can reduce the total number of cases, sotrovimab is an important treatment option for those who become ill with COVID-19 and are at high risk—allowing them to avoid hospitalization or worse,” she said in a statement.

At least Regeneron and Lilly have signed supply deals with the federal government, both covering potentially 1 million-plus doses of their products. Without a contract, GSK and Vir will have to sell sotrovimab on their own.

Recognizing that government contracts are “a defined route” for patients to access COVID treatments,    GSK has been in ongoing conversations with governments around the world, including in the U.S., a company spokesperson said in a statement. For now, it's working through existing commercial channel

, hoping to make sotrovimab available to appropriate patients in the coming weeks. 

RELATED: Feds stop sending Eli Lilly’s COVID-19 cocktail to Illinois on concerns of P.1 variant

Meanwhile, the increase in SARS-CoV-2 variants has raised concerns about the efficacy of existing antibody drugs, especially single-agent therapies. In fact, the FDA recently revoked its authorization for Lilly’s bamlanivimab monotherapy, based on findings of variant resistance.

On the dual-antibody front, use of Lilly’s bamlanivimab-etesevimab combo has been halted in Illinois based on reduced potency against the P.1 variant, which was first identified in Brazil. Thursday, more states followed suit.

As part of the emergency authorization, the FDA said it may require GSK to assess sotrovimab’s activity against any potential variants. The same item was recently added to authorizations for Lilly and Regeneron’s drugs a few weeks ago.

According to results from experiments in lab dishes that GSK and Vir presented to the FDA, sotrovimab maintained strong neutralizing ability against all pseudotyped virus-like particles mimicking existing variants, including P.1. and B.1.351, which was first identified in South Africa, as well as the B.1.617 version that’s responsible for the latest surge of COVID cases in India.

“I believe that sotrovimab is a critical new treatment option in the fight against the current pandemic and potentially for future coronavirus outbreaks as well,” Vir CEO George Scangos said in a statement Wednesday.

RELATED: Regeneron eyes prevention nod for COVID-19 antibody cocktail with simpler injection

Sotrovimab’s current authorization is for an intravenous infusion. GSK and Vir are planning to start two phase 3 trials of an intramuscular injection by the end of June. The Comet-Tail study will focus on high-risk outpatients, and the Comet-Star trial will examine whether the drug can prevent symptomatic disease in uninfected adults, a use where Lilly and Regeneron have reported positive outcomes.

Like many other anti-coronavirus antibodies, sotrovimab previously failed to move the needle in hospitalized patients.

Besides sotrovimab, GSK and Vir are moving forward with a second antibody candidate, dubbed VIR-7832, in an ongoing phase 1b/2a trial in mild-to-moderate COVID patients.

Editor's Note: The story has been updated with additional comments from GSK.