Objective: This study compares once-daily ropinirole 24-h prolonged release and three-times-daily ropinirole immediate release in patients with early Parkinson's disease.
Methods: This multicentre, double-blind, non-inferiority crossover study involved 161 patients randomized to one of four formulation sequences: (1) immediate release-immediate release-prolonged release; (2) immediate release-prolonged release-prolonged release; (3) prolonged release-prolonged release-immediate release; (4) prolonged release-immediate release-immediate release. During a 12-week dose-titration period, ropinirole immediate release was titrated according to the approved labelling; titration of ropinirole 24-h prolonged release started at a higher dose and was more rapid. Patients then entered three consecutive, flexible-dose, 8-week maintenance periods. At the end of the first maintenance period, half of the patients in each formulation group switched to the same or closest dose of the alternative formulation; remaining patients switched at the end of the second maintenance period.
Results: At the end of titration, before the first dose switch, there were substantial reductions in mean Unified Parkinson's Disease Rating Scale (UPDRS) motor scores. During maintenance periods, both groups showed similar efficacy on the UPDRS motor score. Overall mean (standard error) change from period baseline was -0.1 (0.28) for ropinirole 24-h prolonged release, and 0.6 (0.30) for ropinirole immediate release (adjusted mean treatment difference -0.7; 95% confidence interval [CI]: -1.51, 0.10; p = 0.0842). The upper limit of the 95% CI was less than the predefined threshold of 3 points for non-inferiority. Ropinirole 24-h prolonged release was well-tolerated when titrated more rapidly than ropinirole immediate release; overnight switching between formulations was also well-tolerated. Study limitations included complexity of the non-inferiority study design and the forced dose-titration schedule.
Conclusion: Ropinirole 24-h prolonged release was effective and well-tolerated in patients with early Parkinson's disease.