ABSTRACT
INTRODUCTION: There has been no clinical data on Japanese patients with Parkinson's disease with which to examine whether motor symptoms improve and to assess the safety profile after the dose of ropinirole was increased in those who had not achieved an optimal response to the ropinirole immediate-release formulation 15 mg/day or the controlled-release (CR) formulation 16 mg/day. METHODS: This was a multicenter, randomized, double-blind study, followed by an open-label, long-term study. Participants were randomized at a ratio of 3:1 to the high-dose ropinirole CR (18-24 mg/day) group or the maintenance ropinirole CR 16 mg/day group. RESULTS: In the high-dose ropinirole CR group (N = 61), the Japanese unified Parkinson's disease rating scale Part III total score at week 12 was significantly decreased compared with the baseline total score (-4.8 ± 5.95, [95% CI, -6.3 to -3.2], p < 0.001). However, a comparable decrease was also observed in the maintenance ropinirole CR 16 mg/day group (N = 20) (-5.7 ± 5.18, [95% CI, -8.1 to -3.3]), with no statistically significant difference in the adjusted mean change between the high-dose and maintenance groups (0.5 [95% CI, -2.4 to 3.4]). Plasma drug concentrations increased at doses higher than 16 mg/day, but did not increase significantly in a dose-dependent manner at doses of 18-24 mg/day. No adverse events were found that would affect the known safety profile of ropinirole. CONCLUSION: This study did not demonstrate the difference in efficacy between the high-dose ropinirole CR group and the maintenance ropinirole CR group. CLINICAL TRIAL REGISTRATION: ClinicalTrials.gov identifier: NCT01929317.
