By Robb M. Stewart

Regeneron Pharmaceuticals Inc.'s antibody cocktail is being strongly recommended for Covid-19 patients who aren't hospitalized in newly updated National Institutes of Health treatment guidelines, the biotechnology company said Friday.

The NIH's Covid-19 guidelines recommend that casirivimab with imdevimab, a treatment known as REGEN-COV, be used in non-hospitalized Covid-19 patients at high risk of clinical progression.

Its new guidelines are based in part on clinical data involving more than 4,500 outpatients showing that REGEN-COV significantly reduced the risk of hospitalization or death by 70% compared with a placebo, Regeneron said.

The U.S. Food and Drug Administration recently authorized updated emergency use authorization fact sheets for all authorized monoclonal antibody treatments.

Regeneron said some NIH panel members recommended REGEN-COV as the preferred antibody cocktail for Covid-19 in areas where variants are common, given the therapy's potency in vitro against variants first identified in the U.K., Brazil, South Africa, New York and California. The members acknowledged that it isn't known whether in vitro susceptibility data correlates with clinical outcomes, it said.

Although REGEN-COV isn't currently recommended for hospitalized Covid-19, the company said that the panel recommended its use should be considered for people with mild-to-moderate Covid-19 who are hospitalized for a reason other than Covid-19 but who otherwise meet emergency use authorization criteria.

REGEN-COV is a cocktail of two monoclonal antibodies that was designed to block infectivity of SARS-CoV-2, the virus that causes Covid-19. The virus-neutralizing antibodies that form the cocktail bind to the critical receptor binding domain of the virus's spike protein, which diminishes the ability of mutant viruses to escape treatment and protects against spike variants that have arisen in the human population, Regeneron said.

Under an emergency use authorization issued by the FDA, REGEN-COV is currently available in the U.S. to treat mild-to-moderate Covid-19 in adults, as well as in pediatric patients at least 12 years of age and weighing at least 40 kilograms, who have received positive results of direct SARS-CoV-2 viral testing and are at high risk for progressing to severe Covid-19 and/or hospitalization.

Regeneron said it is collaborating with Roche Holding AG to increase global supply of REGEN-COV, with Roche primarily responsible for development and distribution outside the U.S.

Write to Robb M. Stewart at robb.stewart@wsj.com

(END) Dow Jones Newswires

04-09-21 0905ET