By Joseph Walker

A monoclonal-antibody drug reduced hospitalizations or death from Covid-19 by 85% compared with a placebo in a clinical trial, said Vir Biotechnology Inc. and GlaxoSmithKline PLC, the drug's developers.

Based on the positive results, the companies said Wednesday they will immediately ask health regulators in the U.S. and other countries to authorize the therapy, which would add to the arsenal of Covid-19 treatments that help keep infected people out of hospitals.

If authorized, the medicine would be the fourth antibody drug available in the U.S. after ones made by Eli Lilly & Co. and Regeneron Pharmaceuticals Inc. Then-President Donald Trump praised Regeneron's for his recovery, but the drugs have been lightly used.

Vir and Glaxo said that an independent monitoring committee recommended the study be stopped early because an interim analysis of data from 583 study subjects showed the drug, called VIR-7831, was highly effective.

"We look forward to the possibility of making VIR-7831 available to patients as soon as possible and to further exploring its potential in other settings," said Hal Barron, Glaxo's chief scientific officer and president of research and development.

The companies didn't disclose detailed study results, such as the percentage of patients who were hospitalized or died.

Study volunteers will continue to be monitored for 24 weeks, and more data will be released after the study is completed, the companies said. The study is evaluating patients with mild or moderate Covid-19 symptoms who are at a high risk of developing severe disease.

Monoclonal antibodies are the only treatments authorized for patients early in the course of disease who are at high risk of becoming hospitalized. However, many of the available doses have gone unused because of the logistical challenges the drugs present for hospitals, such as finding space and staff to oversee the infusions.

Some patients have said it is difficult to find treatment sites to receive the drugs. In response, HHS, Eli Lilly and Regeneron have sponsored online infusion-site locator tools.

Nationwide, 34% of the doses allocated to states are administered to patients, a spokeswoman for the Department of Health and Human Services said last week.

Vir and Glaxo said a separate study of VIR-7831 showed it remains effective against new coronavirus variants identified in the U.K., South Africa and Brazil that scientists worry could prove resistant to monoclonal antibody drugs.

A scientific paper detailing the variant study results will be published online on a so-called preprint server, the companies said. Preprint servers are used to disseminate research findings before they are published in peer-reviewed journals.

"These findings, paired with our pending publication of resistance data, demonstrate the potential of VIR-7831 to prevent the most severe consequences of Covid-19 and highlight its potential ability to protect against the current circulating strains of the virus," said Vir Chief Executive George Scangos.

Write to Joseph Walker at joseph.walker@wsj.com

(END) Dow Jones Newswires

03-10-21 2249ET