GENEVA — The U.N. health agency says the world’s largest randomized trial of COVID-19 treatments found “conclusive evidence” that remdesivir, a drug used to treat U.S. President Donald Trump when he fell ill, has little or no effect on severe cases.

The World Health Organization has announced long-awaited results of its six-month “Solidarity Therapeutics Trial” that endeavored to see if existing drugs might have an effect on the coronavirus.

The study, which was not peer-reviewed, found that four treatments tested — remdesivir, hydroxychloroquine, lopinavir/ritonavir and interferon — had “ little or no effect on 28-day mortality or the in-hospital course of COVID-19 among hospitalized patients.”

Remdesivir was the only drug of the four that had not largely been ruled out as ineffective in fighting COVID-19.