Prolonged-Release (PR) Oxycodone/Naloxone Improves Bowel Function Compared with Oxycodone PR and Provides Effective Analgesia in Chinese Patients with Non-malignant Pain: A Randomized, Double-Blind Trial

Introduction Prolonged-release oxycodone/naloxone (OXN PR), combining an opioid analgesic with selective blockade of enteric mu-opioid receptors, provided effective analgesia and improved bowel function in patients with moderate-to-severe pain and opioid-induced constipation in clinical trials predominantly conducted in Western countries. This double-blind randomized controlled trial investigated OXN PR (N = 116) versus prolonged-release oxycodone (OXY PR, N = 115) for 8 weeks at doses up to 50 mg/day in patients with moderate-to-severe, chronic, non-malignant musculoskeletal pain and opioid-induced constipation recruited in China. Methods A total of 234 patients at least 18 years of age with non-malignant musculoskeletal pain for more than 4 weeks that was moderate-to-severe in intensity and required round-the-clock opioid therapy were randomized (1:1) to OXN PR or OXY PR. The primary endpoint was bowel function using the Bowel Function Index (BFI). Secondary endpoints included safety, Brief Pain Inventory-Short Form (BPI-SF), use of analgesic and laxative rescue medication, and health-related quality of life (EQ-5D). Results While BFI scores were comparable at baseline, at week 8 improvements were greater with OXN PR vs OXY PR (least squares mean [LSM] difference (95% CI) - 9.1 (- 14.0, - 4.2); P < 0.001. From weeks 2 to 8, mean BFI scores were in the range of normal bowel function (<= 28.8) with OXN PR but were in the range of constipation (> 28.8) at all timepoints with OXY PR. Analgesia with OXN PR was similar and non-inferior to OXY PR on the basis of modified BPI-SF average 24-h pain scores at week 8: LSM difference (95% CI) - 0.3 (- 0.5, - 0.1); P < 0.001. The most frequent treatment-related AEs were nausea (OXN PR 5% vs OXY PR 6%) and dizziness (4% vs 4%). Conclusion OXN PR provided clinically meaningful improvements in bowel function and effective analgesia in Chinese patients with moderate-to-severe musculoskeletal pain and pre-existing opioid-induced constipation.