Despite the deaths, the FDA approved the drug under its accelerated approval program, which allows the agency to clear innovative drugs based on promising preliminary results.
Last week, the consumer advocacy group Public Citizen criticized that approach, noting the drug's outstanding safety issues.
"The fact that bedaquiline is part of a new class of drug means that an increased level of scrutiny should be required for its approval," the group states. "But the FDA had not yet answered concerns related to unexplained increases in toxicity and death in patients getting the drug."
The FDA said it approved the drug based on two mid-stage studies enrolling 440 patients taking Sirturo. Both studies were designed to measure how long it takes patients to be free of tuberculosis.
Results from the first trial showed most patients taking Sirturo plus older drugs were cured after 83 days, compared with 125 days for those taking a placebo plus older drugs. The second study showed most Sirturo patients were cured after 57 days.