Duloxetine shows efficacy in cutting pain from chemotherapy

FDA Highlights by Bruce Sylvester – Patients suffering chemotherapy-induced peripheral neuropathy treated with the anti-depressant duloxetine for 5 weeks achieved a greater reduction in pain compared with patients using a placebo, researchers reported in the April 3, 2013 issue of JAMA.

The authors wrote that 5 weeks of duloxetine treatment, “…was associated with a statistically and clinically significant improvement in pain compared with placebo.”

As background they noted that about 20 to 40 percent of cancer patients  who are treated with neurotoxic chemotherapy, taxanes, platinums, vinca alkaloids or bortezomib, will develop painful chemotherapy-induced peripheral neuropathy, which can persist from months to years beyond chemotherapy completion.

Several prior phase 3 studies have suggested duloxetine has efficacy for painful diabetic neuropathy.

Ellen M. Lavoie Smith, Ph.D., of the University of Michigan School of Nursing, Ann Arbor, and colleagues conducted a randomized phase 3 trial to examine whether duloxetine treatment would reduce chemotherapy-induced peripheral neuropathic pain.

They enrolled 231 subjects, 25 years or older, who were being treated at community and academic settings between April 2008 and March 2011. Study follow-up was completed July 2012.

The subjects were stratified according to chemotherapeutic drug and comorbid pain risk. They were randomized to receive either duloxetine followed by placebo or placebo followed by duloxetine.

Eligible subjects had showed a pain score of at least 4 on a scale of 0 to 10 (measuring average chemotherapy-induced pain) after receiving paclitaxel, other taxane, or oxaliplatin treatment.

Initial dosing was 1 capsule daily of either 30 mg of duloxetine or placebo for the first week, followed by 2 capsules of either 30 mg of duloxetine or placebo daily for 4 additional weeks.

The researchers reported that, at the end of the initial treatment period, patients in the duloxetine-first group achieved a larger decrease in average pain (average change score, 1.06) than those in the placebo-first group (average change score 0.34). The observed average difference in the average pain score between the duloxetine-first and placebo-first groups was 0.73. Of the patients treated with duloxetine first, 59 percent achieved “any decrease in pain” vs. 38 percent of patients treated with placebo first. Thirty percent of duloxetine-treated patients reported no change in pain and 10 percent reported increased pain.

The results also suggested that patients treated with platinums (oxaliplatin) experienced more benefit from duloxetine than those who received taxanes.

There was also greater pain-related quality-of-life improvement for subjects treated with duloxetine during the initial treatment than for those treated with placebo.