(Reuters) - Ariad Pharmaceuticals Inc discontinued a late-stage trial of its cancer drug after some patients developed blood clots, sending its shares crashing 42 percent on fears that a version of the drug already on the market may be withdrawn.
The drug, Iclusig, was granted accelerated approval by the U.S. Food and Drug Administration in December to treat two rare forms of blood cancer, but only with labels warning of the potential for blood clots and liver toxicity.
"People are afraid that they're going to have to take the drug off the market," Summer Street Research analyst Carol Werther told Reuters.
"I don't think it will be (withdrawn), because there's a place for it in patients who have no treatment and the risk/reward would be beneficial for them."
Iclusig is approved to treats adult patients with chronic myeloid leukemia (CML) and Philadelphia chromosome positive acute lymphoblastic leukemia, who are resistant or intolerant to older drugs. The discontinued trial was testing the drug as a treatment for patients with newly diagnosed CML.
Ariad's Chief Scientific Officer, Tim Clackson, said he did not expect the drug to be withdrawn, but that it was likely an FDA advisory panel would evaluate the risks and benefits of the drug next year.
He added that Ariad was in discussions with the FDA to finalize a new label for Iclusig, the company's only drug on the market.
Ariad said on October 9 that it was halting enrollment across eight studies involving Iclusig, following reports that patients in the trials were developing blood clots and heart damage.
Two days later, the regulator recommended that patients taking the drug and their physicians weigh the benefits of treatment with Iclusig against the possibly increased risks.
The company said on Friday that enrollment in remaining seven mid-stage trials were still on hold.
Ariad said the termination of the late-stage trial would not hurt the European launch of the drug in its two approved forms, but expected that safety data on the label would be updated.
Iclusig was approved to treat the two rare blood cancers by European Commission in July.
Ariad shares, which have lost about three-quarters of their value since October9, were down 38 percent at $2.78 in afternoon trade on the Nasdaq. They hit a three-year low of $2.62 earlier in the day.
Reporting By Vrinda Manocha in Bangalore; Editing by Rodney Joyce, Maju Samuel