Sanofi has halted a global phase 3 trial evaluating its investigational hemophilia drug fitusiran after reports of adverse events.

Fitusiran is a once-monthly, subcutaneously administered drug designed to treat hemophilia A and B by blocking antithrombin, a protein that inhibits blood clotting and causes excessive bleeding.

Sanofi halted the study following a recommendation by the trial’s independent data monitoring committee. The company said it is investigating reports of nonfatal thrombotic events in trial participants.