WASHINGTON (AP) -- Shares of Ariad Pharmaceuticals plunged Friday for the second time this week, after the Food and Drug Administration said it was investigating reports of dangerous blood clots with the company's leukemia drug disclosed on Wednesday.
THE SPARK: The FDA said it is evaluating data recently disclosed by Ariad that its cancer drug Iclusig can cause life-threatening blood clots and narrowing blood vessels in patients with leukemia. Ariad reported that 11.8 percent of patients treated with Iclusig in a clinical study had suffered serious blood clots in an artery after two years of research. That's more than the company had previously reported: after collecting 11 months' worth of data from the study it said 8 percent of patients had those side effects.
Ariad said about 20 percent of patients treated with the drug experienced a serious or non-serious blood vessel event.
The Food and Drug Administration has halted enrollment of new patients in all clinical trials of Iclusig, and patients who are being treated with the drug in those trials will have their dosages reduced. Ariad said it is consulting with the FDA and other health regulators about changing the label on Iclusig to reflect the new information.
The FDA said in an online posting Friday that doctors should weigh the risks and benefits of treating patients with Iclusig. Patients taking the drug "should seek immediate medical attention if they experience symptoms suggesting a heart attack such as chest pain or pressure, pain in their arms, back, neck or jaw, or shortness of breath; or symptoms of a stroke such as numbness or weakness on one side of the body, trouble talking, severe headache, or dizziness."
THE BIG PICTURE: The Food and Drug Administration approved Iclusig in December to treat two rare types of leukemia. Ariad reported $13.9 million in Iclusig sales during the second quarter. European Union regulators approved the drug in July, and the Cambridge, Mass., company is running other clinical trials in the hopes of broadening Iclusig's marketing approval and increasing sales.
SHARE ACTION: Shares of Ariad Pharmaceuticals Inc. dropped 76 cents, or 14 percent to $4.65 in midday trading Friday. On Wednesday the stock had its biggest one-day drop ever, falling to $4 at the session low, its lowest price since November 2010.