Sales of a promising leukemia drug, Iclusig, are being suspended because of “the risk of life-threatening blood clots and severe narrowing of blood vessels,” the Food and Drug Administration said on Thursday.The drug, also known as ponatinib, has been linked to severe and sometimes fatal heart attacks and strokes, blindness and loss of blood flow in the extremities serious enough to require amputation. In some cases, the problems or deaths occurred as soon as two weeks after patients began taking the drug, the agency said in a statement. It also said some of the people affected had no risk factors for heart disease, and some were in their 20s.
Iclusig was approved less than a year ago to treat chronic myeloid leukemia. The risk of blood clots was known, and the label carried a warning. But over time, the problems turned out to be much worse than they appeared in the studies performed before the drug was approved. In those studies, 8 percent of people taking the drug had serious blood clots in their arteries, and 3 percent had blood clots in veins.Now, the F.D.A. reports, 24 percent of patients studied a median of 1.3 years and 48 percent studied a median of 2.7 years had “serious adverse vascular events.”