Averting COVID Hospitalizations With Monoclonal Antibodies

Medscape
14 Jan, 2021 ,

USA has allocated more than 641,000 monoclonal antibody treatments for outpatients to ease pressure on strained hospitals, but officials from Operation Warp Speed report that more than half of that reserve sits unused as clinicians grapple with best practices. Monoclonal antibody drugs are based on the natural antibodies that the body uses to fight infections. They work by binding to a specific target and then blocking its action or flagging it for destruction by other parts of the immune system.

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The United States has allocated more than 641,000 monoclonal antibody treatments for outpatients to ease pressure on strained hospitals, but officials from Operation Warp Speed report that more than half of that reserve sits unused as clinicians grapple with best practices.

There are space and personnel limitations in hospitals right now, Janet Woodcock, MD, therapeutics lead on Operation Warp Speed, acknowledges to Medscape Medical News. "Special areas and procedures must be set up." And the operation is in the process of broadening availability beyond hospitals, she points out.

But for frontline clinicians, questions about treatment efficacy and the logistics of administering intravenous drugs to infectious outpatients loom large.

More than 50 monoclonal antibody products that target SARS-CoV-2, the virus that causes COVID-19, are now in development. The US Food and Drug Administration (FDA) has already issued Emergency Use Authorization (EUA) for two such drugs on the basis of phase 2 trial data — bamlanivimab, made by Eli Lilly, and a cocktail of casirivimab plus imdevimab, made by Regeneron — and another two-antibody cocktail from AstraZeneca, AZD7442, has started phase 3 clinical trials. The Regeneron combination was used to treat President Donald Trump when he contracted COVID-19 in October.

Monoclonal antibody drugs are based on the natural antibodies that the body uses to fight infections. They work by binding to a specific target and then blocking its action or flagging it for destruction by other parts of the immune system. Both bamlanivimab and the casirivimab plus imdevimab combination target the spike protein of the virus and stop it from attaching to and entering human cells.

Targeting the Spike Protein Out of the Hospital

The antibody drugs covered by 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 disease progression. They are approved to treat patients older than on 12 years with mild to moderate COVID-19 who are at high risk of progressing to severe disease or hospitalization. They are not authorized for use in patients who have been hospitalized or who are on ventilators. The hope is that antibody drugs will reduce the number of severe cases of COVID-19 and ease pressure on overstretched hospitals.

This is important because it targets the greatest need in COVID-19 therapeutics, says Rajesh Gandhi, MD, an infectious disease physician at Harvard Medical School in Boston, who is a member of two panels evaluating COVID-19 treatments: one for the Infectious Disease Society of America and the other for the National Institutes of Health. "Up to now, most of the focus has been on hospitalized patients," he says, but "most COVID-19 patients are outpatients, so we need something to keep them from getting worse."