Evaluation of the efficacy of duloxetine and venlafaxine in chemotherapy-induced neuropathy in cancer patients: a double-blind multicenter randomized clinical trial.

BACKGROUND: Chemotherapy-induced peripheral neuropathy is a common non-hematologic complication and a major dose-limiting factor in cancer treatment, potentially reducing patient survival. Duloxetine and venlafaxine, antidepressant drugs, have demonstrated efficacy in managing neuropathic pain associated with diabetes and fibromyalgia in several studies.

METHODS: In this randomized, double-blind clinical trial, cancer patients undergoing chemotherapy were assessed for neuropathy and pain using the Patient Neurotoxicity Questionnaire and McGill Pain Questionnaire at baseline, 6 weeks, and 12 weeks. Patients were randomized to receive either duloxetine (Group A: 30 mg daily, increasing to 60 mg daily after 1 week), venlafaxine (Group B: 37.5 mg daily, increasing to 75 mg daily after 1 week), or a placebo (Group C).

RESULTS: Among 141 randomized patients (61% female; mean age 64.4 years), no significant difference in pain scores was observed between groups at the primary endpoint of week 6 (P = 0.59). At the secondary endpoint of week 12, a statistically significant difference between groups emerged (P = 0.03), driven by a reduction in pain scores in the duloxetine group compared with placebo (post hoc P = 0.03). Within-group reductions were significant for both duloxetine (P = 0.002) and venlafaxine (P = 0.007) at 12 weeks.

CONCLUSION: This trial did not meet its primary endpoint at 6 weeks with duloxetine or venlafaxine compared to placebo. Secondary analyses at 12 weeks suggest that only duloxetine may provide clinically meaningful symptom relief. Venlafaxine findings remain inconclusive, as within-group improvements did not translate into statistically significant between-group superiority.