An Open-Label, 52-Week, Phase III Trial of Duloxetine in Japanese Patients with Chronic Low Back Pain.

OBJECTIVE: To evaluate the safety and efficacy of duloxetine treatment for 52 weeks. DESIGN: Multicenter, open-label, phase III clinical study. SETTING: Forty-one medical institutions in Japan. SUBJECTS: Japanese patients with chronic low back pain (CLBP). METHODS: Duloxetine 60 mg once-daily was administered for 52 weeks. Safety was evaluated based on adverse events (AEs), vital signs, laboratory test values, electrocardiogram, Columbia-Suicide Severity Rating Scale, and occurrence of falls. The efficacy outcome measures were the Brief Pain Inventory (BPI; average pain, worst pain, least pain, and pain right now), BPI Interference, Patient's Global Impression of Improvement (PGI-I), Clinical Global Impressions of Severity (CGI-S), Roland-Morris Disability Questionnaire-24 (RDQ-24), 36-Item Short-Form Health Survey (SF-36), and European Quality of Life-5 Dimensions Questionnaire (EQ-5D). RESULTS: In total, 151 patients (83 who completed a 14-week placebo-controlled superiority trial and 68 newly registered patients) were enrolled. The incidence rates of AEs and adverse drug reactions (ADRs) were 86.1% and 50.3%, respectively. ADRs with an incidence of ≥5% were somnolence, constipation, nausea, and dry mouth. Treatment discontinuation for AEs occurred in 16 patients. A significant reduction in the BPI average pain score (mean ± SD) was observed at all assessment time points from week 2 (-1.02 ± 1.37) to week 50 (-2.26 ± 1.63), compared with baseline. BPI pain severity (worst pain, least pain, and pain right now), BPI Interference, PGI-I, CGI-S, RDQ-24, SF-36, and EQ-5D showed significant improvement. CONCLUSION: Japanese patients with CLBP had significant pain reduction over 52 weeks without new safety concerns.

Randomized, Double-blind, Placebo-controlled Phase III Trial of Duloxetine Monotherapy in Japanese Patients With Chronic Low Back Pain.

STUDY DESIGN: A 14-week, randomized, double-blind, multicenter, placebo-controlled study of Japanese patients with chronic low back pain (CLBP) who were randomized to either duloxetine 60 mg once daily or placebo. OBJECTIVE: This study aimed to assess the efficacy and safety of duloxetine monotherapy in Japanese patients with CLBP. SUMMARY OF BACKGROUND DATA: In Japan, duloxetine is approved for the treatment of depression, diabetic neuropathic pain, and pain associated with fibromyalgia; however, no clinical study of duloxetine has been conducted for CLBP. METHODS: The primary efficacy measure was the change in the Brief Pain Inventory (BPI) average pain score from baseline to Week 14. Secondary efficacy measures included BPI pain (worst pain, least pain, pain right now), Patient's Global Impression of Improvement, Clinical Global Impressions of Severity, and Roland-Morris Disability Questionnaire, among other measures, and safety and tolerability. RESULTS: In total, 458 patients were randomized to receive either duloxetine (n = 232) or placebo (n = 226). The BPI average pain score improved significantly in the duloxetine group compared with that in the placebo group at Week 14 [-2.43 ±â€Š0.11 vs. -1.96 ±â€Š0.11, respectively; between-group difference (95% confidence interval), - 0.46 [-0.77 to-0.16]; P = 0.0026]. The duloxetine group showed significant improvement in many secondary measures compared with the placebo group, including BPI pain (least pain, pain right now) (between-group difference: -1.69 ±â€Š0.10, P = 0.0009; -2.42 ±â€Š0.12, P P = 0.0230, respectively), Patient's Global Impression of Improvement (2.46 ±â€Š0.07, P = 0.0026), Clinical Global Impressions of Severity (-1.46 ±â€Š0.06, P = 0.0019), and Roland-Morris Disability Questionnaire (-3.86 ±â€Š0.22, P = 0.0439). Adverse events occurring at a significantly higher incidence in the duloxetine group were somnolence, constipation, nausea, dizziness, and dry mouth, most of which were mild or moderate in severity and were resolved or improved. CONCLUSION: Duloxetine 60 mg was effective and well tolerated in Japanese CLBP patients. LEVEL OF EVIDENCE: 2.