Ariad Pharmaceuticals Inc. (ARIA:US) tumbled the most ever after U.S. regulators placed a hold on enrollment in all trials of the company’s approved cancer drug Iclusig because of blood clots among participants.
Ariad dropped 66 percent to $5.83 in the biggest decline since the shares started trading publicly in 1994. The company has declined 70 percent this year.
Iclusig, approved last year for two rare forms of leukemia, will continue to be given to people in the trials, with some doses being reduced, Cambridge, Massachusetts-based Ariad said today in a statement. The Food and Drug Administration placed a partial hold on the trials after results from one study found serious arterial thrombosis occurred in 11.8 percent of Iclusig-treated patients and cardiovascular events in 6.2 percent.
“Ariad stock will be in the penalty box pending better clarity on how this increased safety risk will affect current utilization,” Michael Yee, an analyst with RBC Capital Markets, wrote in a note today.
Iclusig was approved based on an accelerated process that relied on a single trial showing the drug helped patients. Companies that gain accelerated approval must conduct additional study to prove the drug is effective.
The FDA also asked Ariad for additional cardiovascular safety data, according to the agency’s approval letter to the company. Agency reviewers were concerned that about 8 percent of patients experienced serious events related to blood supply restriction, according to a summary of the FDA’s review. The design of the clinical trial made it difficult to determine whether Iclusig caused the cardiovascular complications, the agency’s reviewers wrote.
The safety issues may lead the FDA to convene a hearing to consider removing Iclusig from the market, said Thomas Smith and Andrew Berens, analysts with Bloomberg Industries.
“Our investigation is ongoing,” Steven Immergut, an FDA spokesman, said. “FDA will consider all safety initiatives and options as we evaluate.”
In addition, results from a trial testing the drug’s use as a first option for patients will be delayed, which “makes it unlikely the stock will meaningfully recover anytime soon since this is the biggest catalyst,” Yee, of RBC Capital, said.
Iclusig will remain on the market, Ariad said. It was approved last year to treat adults with chronic myeloid leukemia and Philadelphia chromosome positive acute lymphoblastic leukemia, two blood and bone marrow diseases. The drug was approved three months ahead of schedule, though a black box warning on its label drove the shares down the most in four years at the time.
Ariad plans to resume studies after changes in dose and other modifications are made. The company also is in consultation with the FDA about possible changes to the drug’s labeling.
“We take this very seriously,” Ariad Chief Executive Officer Harvey Berger said today on a conference call. “Patients come first, and we have to be very focused on ensuring we have safe and effective doses and safe and effective utilization of Iclusig in those patients.”
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