HealthDay News) — The depression and anxiety medication duloxetine is effective in reducing pain in patients with chemotherapy-induced peripheral neuropathy, results of a phase III trial showed.
Patients assigned to duloxetine had significantly higher mean decreases in pain scores compared with patients assigned to placebo (1.06 vs. 0.34, P=0.003), with a mean difference between the two groups of 0.73 (95% CI: 0.26 -1.20), Ellen M. Lavoie Smith, PhD, of the University of Michigan School of Nursing in Ann Arbor, and colleagues reported in the Journal of the American Medical Association.
Furthermore, a higher percentage of patients in the duloxetine group reported some level of decreased pain than patients in the placebo group — 59% vs. 38%.
Previous studies have shown that duloxetine is an effective treatment for diabetic neuropathy, and that serotonin and norepinephrine dual reuptake inhibitors may also work against chemotherapy-induced peripheral neuropathy.
To test whether this is the case, the researchers conducted a randomized, double-blinded, placebo-controlled crossover trial in a population of 220 adult patients with grade I or higher sensory neuropathy following paclitaxel, other taxane, or oxaliplatin treatment.
Participants were assigned one-to-one to either duloxetine followed by placebo or placebo followed by duloxetine for a total of five weeks each and were switched to receive the opposite treatment at weeks 8 to 12.
During the first week, participants were assigned to receive one capsule of placebo or 30 mg of duloxetine, followed by two capsules of placebo or 60 mg of duloxetine during the next 4 weeks. There was a 2-week washout period between phases of the trial.
The primary outcome was decrease in average pain score on the Brief Pain Inventory Short Form (BPI-SF) after 5 weeks of treatment. Secondary outcomes were the effects of duloxetine on quality of life, function and adverse events.
Among those who assigned to receive duloxetine first, pain scores were significantly reduced versus those receiving placebo first, producing a “moderately large” effect size of 0.513, the researchers found.
Relative risk was 2.43 (95% CI: 1.11-5.30) for a 50% reduction in pain with initial drug treatment, and 1.96 (95% CI: 1.15-3.35) for a 30% pain reduction with initial placebo treatment. Patients who received platinums experienced greater pain score improvement from duloxetine than those who received taxanes (P=0.13), data suggested.
On secondary outcomes, patients in the duloxetine group experienced greater decreases in the amount that pain interfered with daily functioning (P=0.01) and significantly improved quality of life (P=0.03) compared with placebo.
Common adverse events associated with treatment included fatigue, insomnia and nausea. There were fewer grade II events reported with duloxetine (16% vs. 27%), but more grade III events (7% vs. 3%) compared with placebo. There were no hematologic, grade IV or grade V events. Adverse event-related drop out was significantly higher in the duloxetine-first group versus placebo-first (11% vs. 1%, P<0.001).
The researchers called for more research to study the long-term outcomes of patients with chemotherapy-induced peripheral neuropathy treated with duloxetine.