Biomea Fusion said on Thursday the U.S. Food and Drug Administration had placed a clinical hold on its ongoing early-to-mid stage study of its experimental drug for type 1 and 2 diabetes, sending its shares down 60% in extended trade.

The drug developer said the FDA cited deficiencies based on the level of possible drug-induced toxic liver disease observed in the completed dose escalation phase of the trial.

Higher doses of up to 400 milligrams, various food intake regimens, medical history and accompanying medications may have contributed to observed liver enzyme elevations, the company said.