Efficacy and safety of oxycodone/naloxone as add-on therapy to gabapentin or pregabalin for the management of chemotherapy-induced peripheral neuropathy in Korea

AIMS: To investigate the efficacy and safety of oxycodone/naloxone in patients with chemotherapy-induced peripheral neuropathy (CIPN) inadequately controlled with pregabalin or gabapentin. METHODS: This 4-week, multicenter, interventional, single-arm phase IV study included 72 Korean patients with CIPN inadequately controlled with pregabalin or gabapentin (Numeric Rating Scale 0-10; NRS ≥4 at baseline). In addition to pregabalin or gabapentin at existing doses, patients received 20/10 mg/day oxycodone/naloxone (up-titrated to 80/40 mg/day as needed). The primary endpoint was change in NRS score after 4 weeks. Secondary endpoints included Functional Assessment of Cancer Therapy/Gynecologic Oncology Group-Neurotoxicity (FACT/GOG-NTX) scores and safety assessments. RESULTS: The mean ± standard deviation (SD) dose of oxycodone/naloxone was 23.3 ± 7.5 mg/day. At week 4, NRS score reduction was 1.29 ± 1.84 points (21.4% reduction; P < 0.0001). Patients on taxane-based chemotherapy experienced a significantly smaller mean change in NRS score at week 4 compared to patients on other chemotherapy (-0.63 ± 1.54 [n = 30] vs. -1.83 ± 1.00 [n = 36]; P = 0.0072). Although there were no significant changes in FACT/GOG-NTX total scores, improvements were observed in the neurotoxicity subscale measuring numbness/tingling of hands (mean ± SD change: -0.27 ± 1.04; P = 0.0427) and feet (-0.60 ± 1.09; P < 0.0001). Forty-two (58.3%) patients reported adverse events. There were no clinically significant changes in laboratory tests or vital signs. CONCLUSION: Oxycodone/naloxone added to pregabalin or gabapentin provided additional pain relief and symptom control in Korean patients with CIPN, without clinically significant safety concerns.