Oxycodone or Higher Dose of Levodopa for the Treatment of Parkinsonian Central Pain: OXYDOPA Trial

Abstract Background Among the different types of pain related to Parkinson's disease (PD), parkinsonian central pain (PCP) is the most disabling. Objectives We investigated the analgesic efficacy of two therapeutic strategies (opioid with oxycodone‐ prolonged‐release (PR) and higher dose of levodopa/benserazide) compared with placebo in patients with PCP. Methods OXYDOPA was a randomized, double‐blind, double‐dummy, placebo‐controlled, multicenter parallel‐group trial run at 15 centers within the French NS‐Park network. PD patients with PCP (≥30 on the Visual Analogue Scale VAS) were randomly assigned to receive oxycodone‐PR (up to 40 mg/day), levodopa/benserazide (up to 200 mg/day) or matching placebo three times a day (tid) for 8 weeks at a stable dose, in add‐on to their current dopaminergic therapy. The primary endpoint was the change in average pain intensity over the previous week rated on VAS from baseline to week‐10 based on modified intention‐to‐treat analyses. Results Between May 2016 and August 2020, 66 patients were randomized to oxycodone‐PR (n = 23), levodopa/benserazide (n = 20) or placebo (n = 23). The mean change in pain intensity was −17 ± 18.5 on oxycodone‐PR, −8.3 ± 11.1 on levodopa/benserazide, and −14.3 ± 18.9 in the placebo groups. The absolute difference versus placebo was −1.54 (97.5% confidence interval CI, −17.0 to 13.90; P = 0.8) on oxycodone‐PR and +7.79 (97.5% CI, −4.99 to 20.58; P = 0.2) on levodopa/benserazide. Similar proportions of patients in each group experienced all‐cause adverse events. Those leading to study discontinuation were most frequently observed with oxycodone‐PR (39%) than levodopa/benserazide (5%) or placebo (15%). Conclusions The present trial failed to demonstrate the superiority of oxycodone‐PR or a higher dose of levodopa in patients with PCP, while oxycodone‐PR was poorly tolerated. © 2024 The Author(s). Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.