Cancer patients on certain chemotherapies often experience a painful tingling in their extremities called peripheral neuropathy, and a new study suggests the antidepressant Cymbalta may be the first treatment to work against the condition.
In the small study, 59 percent of patients who'd experienced peripheral neuropathy said that they gained relief after taking Cymbalta (duloxetine), compared to 39 percent who took a "dummy" pill.
Taking Cymbalta daily "decreases chronic chemotherapy-induced neuropathy and pain severity in the majority of patients who take it and it improves function and quality of life," said study author Ellen Lavoie Smith, an assistant professor at the University of Michigan's School of Nursing. She said the drug is also "very well tolerated" by most patients.
Smith spoke at a news briefing Sunday at the annual meeting of the American Society of Clinical Oncology (ASCO) in Chicago. The findings were to be formally presented Monday.
One expert was also encouraged by the findings.
"Patients undergoing chemotherapy have to face a multitude of changes, both physically and mentally, and improving their quality of life during this phase of their lives is of utmost importance," said Dr. Stephanie Bernik, chief of surgical oncology at Lenox Hill Hospital in New York City. "It is extremely exciting that there is now a drug we can offer that can reduce this terrible side effect and make chemotherapy more tolerable."
Chemotherapy-induced peripheral neuropathy involves a tingling and numbness in the hands and feet, and is a common side effect of chemotherapies such as the platinum-based medications or taxanes (drugs such as Taxol or Taxotere). It is estimated that up to 30 percent of patients who receive these medications experience neuropathy, and the side effect is a contributing factor to patients dropping treatment.
In the worst cases, "some patients endure this painful neuropathy for months and possibly as long as years following completion of therapy," Smith said. "So it's chronic, it's very distressing and disabling, and then in addition there's really nothing to date that we know is effective in treating the problem."
The new study, funded by the U.S. National Cancer Institute, involved 231 cancer patients who had developed peripheral neuropathy after taking either the platinum-based cancer drug oxaliplatin or the taxane paclitaxel (Taxol). They were randomly assigned to receive either a half-dose of Cymbalta starting at 30 milligrams (mg) per day for the first week, then the full, 60-mg dose for another four weeks; or a placebo pill for five weeks.
According to Smith, Cymbalta is thought to help ease neuropathy by altering levels of brain neurotransmitters linked to nerve function. The drug is already used to treat diabetic peripheral neuropathy, the study noted.
The study found that more patients taking Cymbalta were more likely to report a decrease in neuropathic symptoms compared to those on the placebo. Smith added that "33 percent of patients in the duloxetine group had at least a 30 percent decrease in pain and 21 percent of patients had at least a 50 percent decrease in pain" -- numbers much higher than those on the placebo pill.
Patients taking Cymbalta also "had a greater decrease in the amount that pain interfered with some very important things -- with general activity, with movement, walking, normal work, relations with people, sleep and enjoyment of life," Smith said.
Still, not everyone in the study gained a benefit and some patients actually experienced an increase in tingling/numbness during the trial. However, this was less frequent for those on Cymbalta (11 percent) than on a placebo (28 percent), the authors said.
Cymbalta may come with side effects of its own, notably fatigue, and 11 percent of patients on Cymbalta reported moderate to severe fatigue versus 3 percent of those taking the dummy pill.
Smith said her team is now working on trying to "predict who might respond [to Cymbalta] so that we can target the use of this drug to the people who are mostly likely to benefit."
Another oncologist said he was heartened by these initial results.
"It's true there are not many great treatments for neuropathy, something that is a common side effect of some of the chemotherapy medications that we use for the most common cancers: lung, colon and breast," said Dr. Cardinale Smith, of the division of hematology/medical oncology at the Tisch Cancer Institute and Mount Sinai School of Medicine, in New York City. "This study adds evidence of a medication that appears to have good efficacy in treating what can be a debilitating toxicity."
ASCO spokesman Dr. Nicholas Vogelzang, who moderated the press briefing, said he sees far too much neuropathy in his patients, many of whom receive platinum-based chemotherapy.
I used Cymbalta for a year. The first 8 months were great in alleviating my all-over pain, which is why I was taking it. After that, slowly it came back until I asked to be taken off. In the first few days I had pounding of my heart which was so bad I never slept all night. MD put me on another blood pressure pill which helped after upping the dosage a couple times. After weaning off, heart pounding & insomnia started again.