A randomized, double-blind, placebo-controlled Phase III trial of duloxetine in Japanese patients with knee pain due to osteoarthritis

To examine the efficacy and safety of duloxetine in Japanese patients with knee pain due to osteoarthritis. Patients were randomized to receive duloxetine 60 mg/day or placebo for 14 weeks in a double-blind manner (ClinicalTrials.gov Identifier: NCT02248480). The primary efficacy endpoint was mean change in Brief Pain Inventory pain severity (BPI-Severity) average pain. Secondary endpoints included improvement in other BPI-Severity scales, Patient Global Impression of Improvement, Clinical Global Impressions of Severity, health-related quality of life (HRQoL) scales, range of motion of the knee joint, safety and tolerability, and structural changes on X-ray images. Of the 354 randomized patients, 161 in the duloxetine group and 162 in the placebo group completed the study. BPI-Severity average pain improved significantly with duloxetine vs. placebo (-2.57 vs. -1.80; adjusted mean difference: -0.77; 95% CI: -1.11 to -0.43;