(CHICAGO, IL) – Daily duloxetine therapy effective and well-tolerated for the treatment of painful chemotherapy-induced peripheral neuropathy (CIPN), according to a randomized, double-blind, placebo-controlled Phase 3 trial presented at the 2012 American Society of Clinical Oncology Annual Meeting.
“Duloxetine 60mg daily is the first drug shown to diminish CIPN pain with a large, randomized clinical trial,” said lead author Ellen M. Lavoie Smith, PhD, APRN, School of Nursing, University of Michigan, Ann Arbor, MI. “It decreased chronic CIPN pain severity in the majority of patients and improved function and quality of life.”
Because of suicide risks associated with duloxetine, patients were excluded from the study if they were younger than 25 years or had histories of bipolar disease, major clinical depression, eating disorders, or alcohol abuse.
Patients were randomized to receive duloxetine followed by placebo (n=115) or placebo followed by duloxetine (n=116); initial crossover periods for each group were 6 weeks of drug/placebo followed by 1 week of washout. Of the initially-enrolled 231 participants, 81% completed the interventions and data was analyzed for 87 initial duloxetine-arm patients and 93 patients in the initial placebo arm.
Pain reduction was more pronounced with duloxetine than placebo, with Brief Pain Inventory Short Form score reductions of 59% vs. 38% (for any decrease), and 21% vs. 9% for decreases of 50% or more (P=0.015). There was no difference in efficacy related to chemotherapy type, Dr. Smith and colleagues noted. Quality of life scores (FACT/GOG-NTX and EORTC QLQ-C30) improved significantly with duloxetine (P=0.030 and 0.032, respectively).
Adverse events were rare and not significantly different between duloxetine and placebo; 7% of patients experienced duloxetine-related fatigue. Duloxetine was well tolerated, probably because patients initially self-administered 30mg starting doses, and then ramped up to 60mg doses, Dr. Smith said. However, data regarding concurrent analgesic drug dosages were not collected for the study, she was quick to acknowledge.
Not all patients benefited from duloxetine, Dr. Smith and colleagues noted; pain scores increased during 11% of duloxetine-arm patients. Future research is needed to determine whether or not pain processing abnormalities in the brain, predict patient responses, Dr. Smith said.