Cephalon has warned doctors about at least three deaths linked to its cancer pain drug Fentora, U.S. health regulators said on Thursday.
Cephalon , whose shares fell more than 5%, sent health-care providers letters dated September 10 about serious side effects and deaths that have occurred in patients treated with Fentora, the U.S. Food and Drug Administration said on its Web site.
The deaths occurred in cases where the drug was given to patients who cannot tolerate opioid therapy, or in patients getting the drug inappropriately as a substitution for another drug, such as Cephalon's own Actiq, the company said.
Cephalon spokeswoman Candace Steele said the three deaths occurred over a fairly short period of time during the summer and that they were most likely caused by respiratory failure.
An FDA spokeswoman was not available for comment.
Last year, an investigation by Connecticut's attorney general found that Cephalon illegally promoted drugs for uses for which they are not approved, including Actiq, Cephalon's older cancer pain medicine.
Cephalon is also one of a host of companies that have been subpoenaed in a U.S. congressional probe into off-label treatments, which occurs when doctors prescribe products for uses other than those officially approved by regulators.
Fentora is approved to treat so-called breakthrough pain in patients with cancer who are already receiving and are able to tolerate opioid therapy such as morphine or oxycodone.
The company is seeking approval to expand use of the drug into other pain conditions, such as back pain.
Cephalon shares were down 5.4% to $72.37 in after noon trading on Nasdaq after going as low $72.08 earlier in the session.