Cephalon warns over pain drug deaths

By Kim Dixon and Toni Clarke

WASHINGTON/BOSTON (Reuters) - Cephalon Inc (CEPH.O: Quote, Profile, Research, Stock Buzz) has warned doctors about deaths linked to improper use of its cancer pain drug Fentora, U.S. drug regulators said on Thursday, sending the company's shares down 5 percent.

The U.S. Food and Drug Administration posted on its Web site Cephalon's letter to doctors dated September 10, warning of deaths and serious side effects in patients treated with the pain killer.

Cephalon spokeswoman Candace Steele said the company has received reports of three deaths related to inappropriate prescribing of the drug. The deaths occurred during the summer and are most likely due to respiratory failure, she said.

Two deaths were in patients who could not tolerate narcotics and were prescribed Fentora for headache or migraine. One death was associated with improper dosing, Steele said.

Cephalon also received a report of a person who committed suicide while thought to be on the drug, although Fentora was not prescribed for that patient by a physician.

FDA spokeswoman Susan Cruzan said the agency "takes this very seriously, and is working with the company to assure the safest possible use of this medication."

CIBC Markets analyst Bret Holley said he did not expect doctors to stop prescribing Fentora because it is among potent pain-killing drugs that are known to carry similar risks.

"The risk of death is a serious concern with any strong opioid," Holley said in an investor note. "The headline is scarier than any potential impact on sales."