Efficacy and safety of controlled-release oxycodone for the management of moderate-to-severe chronic non-cancer pain in Japanese patients: Results from an open-label study

Abstract

Purpose: To assess the efficacy and safety of S-8117, an oral, controlled-release formulation of oxycodone hydrochloride, in Japanese patients with chronic non-cancer pain (CNCP). Patients and methods: In this multicenter, non-randomized, open-label, 2-part (part 1, dose-titration followed by maintenance period; part 2, long-term administration period) study at 38 centers in Japan (2013–2015), adult patients with CNCP for ≥12 weeks were administered S-8117. The primary endpoint was proportion of patients with successful maintenance of pain control in part 1 and long-term safety in part 2. Secondary endpoints included time to inadequate analgesia, rate of transition to the maintenance period, and discontinuation due to inadequate analgesia/ adverse events (AEs), Brief Pain Inventory (BPI) pain severity, BPI pain interference, 36-item Short Form Health Survey (SF-36) score, and Western Ontario and McMaster Universities (WOMAC) index, Subjective Opioid Withdrawal Scale (SOWS), Clinical Opioid Withdrawal Scale (COWS), Dependency-2-A (D-2-A), and Dependency-2-B (D-2-B) questionnaires. Results: Of 130 patients (mean age, 63.6 years; women, 62.3%) in the dose-titration period, 95 entered the maintenance period; 60 of 83 who entered the long-term administration period completed it. The proportion of patients (95% confidence interval) with successful maintenance of pain control, transition to maintenance period, and discontinuation due to inadequate analge-sia/AEs was 78.9% (69.4–86.6), 73.1% (64.6–80.5), and 21.1% (13.4–30.6), respectively. Time to inadequate analgesia could not be estimated. Changes from baseline in BPI, SF-36, and WOMAC index scores suggested improvements in pain relief and quality of life. Based on the SOWS, COWS, D-2-A and D-2-B questionnaires, no patient developed clinically relevant withdrawal syndrome or was ascertained to have developed drug dependence. Overall, the incidence of treatment-emergent AEs (TEAEs) was 93.8%; most common TEAEs were constipation (49.2%), nausea (42.3%), nasopharyngitis (34.6%), and somnolence (32.3%). Conclusion: These results demonstrate the efficacy and safety of S-8117 in Japanese patients with CNCP.