Aug. 19, 2010 -- An FDA advisory panel today gave a closely divided vote of support to drugmaker Eli Lilly's application to increase the number of approved uses for one of its best-selling drugs, the antidepressant Cymbalta (duloxetine).
If the FDA follows the panel's advice, which it is not required to do, Cymbalta will become an approved treatment for chronic pain. What kinds of pain is still a matter of debate.
Lilly representatives spent the morning reviewing in-house studies on the safety and effectiveness of Cymbalta in the treatment of chronic lower back pain as well as pain due to osteoarthritis. In separate votes, the panel accepted the company's claims about chronic lower back pain and rejected those concerning osteoarthritis.
Osteoarthritis "is too broad an indication," said panelist Thomas Boyer, MD, of the University of Arizona College of Medicine. "It's not warranted by these studies."
Eight of the other panelists agreed with Boyer. John Markman, MD, director of the University of Rochester Medical Center's Neuromedicine Pain Management Center, was an exception.
"We prescribe it [for osteoarthritis] and find it to be beneficial," said Markman in explaining his yes vote. "Having this indication will ensure [patients] have access to it."
Variety of Uses for Cymbalta
If the FDA approves Lilly's application, it will allow the company to market the drug much more broadly. Panel chairman Jeffrey R. Kirsch, MD, a professor at Oregon Health and Science University in Portland, who voted in favor of approval, expressed concern that ads for the drug were already promoting its use as a pain medication.
More than 14 million prescriptions were written for Cymbalta last year, a threefold increase since its introduction in 2004. In addition to depression, Cymbalta has been approved for the treatment of anxiety, nerve pain caused by diabetes, and fibromyalgia.
According to FDA researcher Rajdeep Gill, PharmD, two-thirds of Cymbalta prescriptions are written to treat conditions for which the drug is not officially approved, including an estimated 14% for pain management. A label change, Gill said, "may expose physicians and patients to an area that is already not uncommon."
In making its case, Lilly representatives argued that adding Cymbalta to the list of drugs approved for the treatment of chronic pain would benefit a significant number of patients who don't respond to other medications or for whom such medications have unacceptable side effects.
"I believe this is going to help chronic pain patients, because it has a separate mechanism [from other types of pain medication]," says Daniel Clauw, MD, a professor of anesthesiology, medicine, and psychiatry at the University of Michigan, speaking on Lilly's behalf.