ANN ARBOR, Mich. -- The antidepressant drug duloxetine, known commercially as Cymbalta, helped relieve painful tingling feelings caused by chemotherapy in 59 percent of patients, a new study finds. This is the first clinical trial to find an effective treatment for this pain.
Chemotherapy-induced peripheral neuropathy is a common side effect of certain chemotherapy drugs. The tingling feeling -- usually felt in the toes, feet, fingers and hands -- can be uncomfortable for many patients, but for about 30 percent of patients, it's a painful sensation. Previous studies have found no reliable way to treat this type of pain.
In the current study, which will be presented Tuesday at the American Society of Clinical Oncology Annual Meeting, researchers looked at 231 patients who reported painful neuropathy after receiving the chemotherapy drugs oxaliplatin or paclitaxel. Patients were randomly assigned to receive duloxetine or a placebo for five weeks. They were asked to report on their pain levels weekly throughout the study.
The researchers found that 59 percent of patients who received duloxetine reported reduced pain, while only 39 percent of those taking placebo did.
"These drugs don't work in everyone. The good news is it worked in the majority of patients. We need to figure out who are the responders. If we can predict who they are, we can target the treatment to the people it's going to work for," said lead study author Ellen M. Lavoie Smith, Ph.D., APRN, AOCN, assistant professor at the University of Michigan School of Nursing and a researcher at the U-M Comprehensive Cancer Center.
Duloxetine has previously been shown to help relieve painful diabetic neuropathy. This type of antidepressant is believed to work on pain by increasing neurotransmitters that interrupt pain signals to the brain.
In this study, participants received a half dose of duloxetine - 30 milligrams a day - the first week before ramping up to a full dose of 60 mg daily for four more weeks. Few severe side effects were reported with this approach. The most common side effect was fatigue.
Treating painful peripheral neuropathy is critical because the condition can lead doctors to limit the patient's chemotherapy dose if the pain becomes too severe.
"In addition to improving symptoms and quality of life, treating peripheral neuropathy pain potentially improves quantity of life if it helps patients avoid decreasing their chemotherapy medications," Smith says.
Often, Smith adds, patients avoid telling their doctors about pain because they do not want their chemotherapy dose decreased.
"Patients make this trade-off sometimes: They don't want to give up the chemotherapy and decide they'd rather have this pain. That's a terrible trade off to make," Smith says.
The researchers' next steps are to determine which patients are most likely to benefit from duloxetine.
Additional authors: Herbert Pang, Ph.D.; Constance Cirrincione, M.S.; Stewart Fleishman, M.D.; Electra D. Paskett, Ph.D.; Tim Ahles, Ph.D.; Camilo Fadul, M.D.; Chetaye Knox; Charles L. Shapiro, M.D.
Funding: National Institutes of Health's National Cancer Institute; drugs and placebo provided by Lilly Pharmaceuticals
Reference: "CRA9013: CALGB 170601: A phase III double blind trial of duloxetine to treat painful chemotherapy-induced peripheral neuropathy (CIPN)," Smith et al. American Society of Clinical Oncology Annual Meeting, June 1-5, 2012