COVID-19: Trial for drug halted after some patients die

A Brazilian study testing the antimalarial drug chloroquine for COVID-19 had to be stopped early in one group of patients taking a high dose of the drug.

Two patients in the high dose group developed a fast, abnormal heart rate known as ventricular tachycardia before they died, according to Live Science.

Chloroquine and the related drug hydroxychloroquine have made headlines in recent weeks after President Donald Trump called the drugs a potential "game-changer" for the treatment of COVID-19.

The Brazilian researchers planned to enroll 440 people in their study to test whether chloroquine is a safe and effective treatment for COVID-19. Participants took either a "high dose" of the drug (600 milligrams twice daily for ten days) or a "low dose" (450 mg for five days, with a double dose only on the first day). The study was "double-blind," meaning that neither the patients nor their doctors knew which dose they were receiving.

However, after enrolling just 81 patients, the researchers saw some concerning signs. Within a few days of starting the treatment, more patients in the high dose group experienced heart rhythm problems than those in the low dose group.