The U.S. Food and Drug Administration (FDA) issued a Drug Safety Communication (DSC) regarding the arthritis and ulcerative colitis drug Xeljanz (and Xeljanz XR), otherwise known as tofacitinib. After studying the results of a large, randomized safety clinical trial of the medicine, the agency stated there was evidence of “serious heart-related events,” including heart attack, stroke, cancer, blood clots, and death.