The U.S. Food and Drug Administration (FDA) granted an Emergency Use Authorization (EUA) to Gilead Sciences (NASDAQ:GILD) to use its investigational antiviral drug remdesivir to treat COVID-19. President Trump made the announcement in the Oval Office along with Gilead Chief Executive Officer Daniel O'Day, and the FDA released a letter confirming the authorization.

Remdesivir hasn't been formally approved to treat any disease, but today's action by the FDA authorizes it for temporary use during the pandemic to treat hospitalized patients with severe COVID-19.

Vials of drugs on a manufacturing line

Image source: Getty Images.

The FDA decision was based on a review of top-line data from two clinical trials. In a placebo-controlled phase 3 trial  conducted by the National Institute for Allergy and Infectious Diseases, 1,063 critically ill patients receiving remdesivir had an average recovery time of 11 days, compared with 15 days in the placebo group. Those receiving the drug also had a lower mortality rate, although the mortality result was not proven with statistical significance. Patients in Gilead's own Simple-1 trial showed improvement as well, but that trial was for comparing two different durations of treatment and wasn't placebo-controlled.

Gilead is donating its entire current supply of the drug at no cost, which amounts to enough to treat 140,000 patients, assuming a course of treatment lasting 10 days. The biotech company is racing to ramp up manufacturing capacity and has set a goal of producing 500,000 treatment courses by October and a million by December. The Simple-1 study, though, suggested that a 5-day course of treatment produced similar results as a 10-day course, so Gilead now believes it will be able to treat far more patients than it thought when it set those goals.