Companies Seek EUA for New COVID Monoclonal Antibody Treatment

Marcia Frellick

March 11, 2021

Editor's note: Find the latest COVID-19 news and guidance in Medscape's Coronavirus Resource Center.

An independent data monitoring committee is recommending stopping enrollment of a phase 3 trial of a monoclonal antibody for COVID-19 because interim results indicate an 85% (P = .002) reduction in hospitalizations or death, two companies have announced.

Vir Biotechnology and GlaxoSmithKline said on Wednesday that they plan to immediately seek emergency use authorization (EUA) from the US Food and Drug Administration (FDA) and authorizations in other countries for its therapy, VIR-7831.

The recommendation was based on results of the randomized, double-blind, multicenter, placebo-controlled COMET-ICE trial, which involved 583 patients with mild to moderate COVID-19.

Raj Gandhi, MD, a physician in the Department of Infectious Diseases at Massachusetts General Hospital and associate professor of medicine at Harvard Medical School, Boston, Massachusetts, told Medscape Medical News that he was intrigued and excited by the data but had questions, for example, how many patients ended up needing hospitalization in the treatment group compared with the placebo group.

"If you have a very small number of patients in the placebo group who have hospitalizations and a very small number of participants in the antibody arm who have hospitalizations, you are less sure of the results, because a few numbers in either direction could change the results," he said.

With a phase 3 trial, the numbers are larger, "and you have more confidence in those results," Gandhi said.

As previously reported by Medscape Medical News, more than 50 monoclonal antibody products that target SARS-CoV-2 are in development.

The FDA in November granted EUAs for both bamlanivimab and the combination of casirivimab and imdevimab for outpatients with mild to moderate COVID-19 at high risk for severe COVID-19.

In February, the FDA granted an EUA for the combination of bamlanivimab and etesevimab, also for the treatment of mild to moderate COVID-19 in patients who are at high risk for progression to severe disease.

In the study of that combination, results showed a 70% reduction in risk for hospitalization or death (P = .0004).

According to Wednesday's press release, "In contrast to other monoclonal antibodies, VIR-7831 binds to a highly conserved epitope of the spike protein, which may make it more difficult for resistance to develop."

Drugs under EUAs do not cure COVID-19, but they have been shown to reduce hospitalizations and visits to the emergency department for patients at high risk for severe disease.

Promising Against Variants

Vir and GlaxoSmithKline also said a new study showed that VIR-7831, which is administered by infusion, was effective against the UK, South African, and Brazilian variants of the coronavirus. That study is pending publication in bioRxiv, the companies said.

Raymund Razonable, MD, professor of medicine and an infectious disease specialist with the Mayo Clinic in Rochester, Minnesota, told Medscape Medical News that the positive news is in line with results he has seen in the clinical performance of other monoclonal antibodies with EUAs.

He pointed to the press release's promise of activity against the most concerning variants and said that that may help VIR-7831 stand out.

"There are data that suggest that the first product, bamlanivimab, has much less efficacy with the South African variety, for example," he said.

He cautioned that the topline results leave questions and that the study has not been peer reviewed.

As reported Medscape Medical News, the monoclonal antibodies have so far been underused: Some 785,000 doses of the therapeutics have been produced, and about a half million have been distributed to states, but about three quarters have gone unused.

Razonable said he hopes promising results like those presented in the press release will help boost uptake.

However, challenges remain, he said.

Not all centers are administering the drugs, so access is poor; the centers must separate the patients with COVID-19 from others receiving infusions; robust data are lacking; and there is a general lack of awareness, so patients aren't requesting the treatments, Razonable said.

Gandhi added that intravenous injection presents staffing challenges because nurses are required, and there are administrative challenges.

"I know many of these companies are trying to make IV infusions shorter. The first were over an hour," he said. "Subcutaneous or intramuscular injections are somewhat easier."

Primary Endpoint

The phase 3 COMET-ICE trial assessed the safety and efficacy of one intravenous infusion of VIR-7831 (500 mg) or placebo in nonhospitalized participants globally. The interim analysis included 291 patients in the treatment arm and 292 in the placebo arm.

The primary efficacy endpoint is the proportion of patients who experience progression of COVID-19, as defined by the need for hospitalization for at least 24 hours or death within 29 days of randomization.

The analysis shows that the treatment was well tolerated, according to the press release.

Of the participants, 63% were Hispanic or Latinx, and 7% were Black. Among these groups, mortality from COVID-19 is disproportionately higher, according to the Centers for Disease Control and Prevention.

"As the trial remains ongoing and blinded with patients continuing to be followed for 24 weeks," the press release said, "additional results, including epidemiology and virology data, will be forthcoming."

George Scangos, PhD, chief executive officer of Vir, said in a statement: "The dual-action design of VIR-7831 to both block viral entry into healthy cells and clear infected cells, as well as its high barrier to resistance, are key distinguishing characteristics."

Razonable is the lead investigator for the casirivimab/imdevimab combination, but compensation goes to his institution.

Marcia Frellick is a freelance journalist based in Chicago. She has previously written for the Chicago Tribune and Nurse.com and was an editor at the Chicago Sun-Times, the Cincinnati Enquirer, and the St. Cloud (Minnesota) Times. Follow her on Twitter at @mfrellick.

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