Faced with mounting evidence that hydroxychloroquine is ineffective in treating COVID-19, three trials of the drug have been terminated.

After finding the drug “very unlikely” to be beneficial, the NIH’s National Heart, Lung and Blood Institute has ended a phase 3 study of the antimalarial for hospitalized COVID-19 patients.

Separately, the NIH’s National Institutes for Allergy and Infectious Diseases (NIAID) shut down its phase 2 study of hydroxychloroquine in combination with the antibiotic azithromycin due to enrollment problems.

Novartis has also discontinued a phase 3 clinical trial of hydroxychloroquine as a COVID-19 treatment in the U.S. because it failed to recruit enough patients. That trial was expected to enroll 440 patients (DID, April 21).

The FDA last week revoked its Emergency Use Authorization (EUA) for hydroxychloroquine and chloroquine after several studies found the antimalarials ineffective against the virus and even dangerous for COVID-19 patients (DID, June 16). — Jordan Williams