Study 3 (Flexible-Dose Trial)

A 36-week, multicenter, double-blind, titration/3-period maintenance, flexible-dose, crossover trial compared the efficacy of ropinirole extended-release tablets with the immediate-release formulation of ropinirole in 161 patients with early phase Parkinson’s disease (Hoehn & Yahr Stages I-III) with limited prior exposure to L-dopa or dopamine agonists. Eligible patients were randomized (1:1:1:1) to 4 treatment sequences (2 were titrated on immediate-release formulation of ropinirole and 2 on ropinirole extended-release tablets). Titration rate of immediate-release formulation of ropinirole was slower than that of the ropinirole extended-release tablets. Patients were titrated during the 12-week titration period to their optimal dosage, based upon tolerance and therapeutic response. This was followed by 3 consecutive 8-week maintenance periods, during which patients were either maintained on the prior formulation or switched to the alternative formulation. All switches were performed overnight by using the approximately equivalent doses of ropinirole. The primary efficacy endpoint was the change of UPDRS motor score within each maintenance period. 

Patients in all 4 groups started out with similar UPDRS motor scores (about 21) at baseline. All groups exhibited similar improvement in UPDRS total motor scores from baseline until the completion of the titration phase, with a change in score of about -9 observed for the groups started on immediate-release formulation of ropinirole and of about -10 for the groups started on ropinirole extended-release tablets. No difference was observed between groups when switches were made between identical formulations or between different formulations. This suggests therapeutic dosage equivalence between the immediate-release formulation of ropinirole and ropinirole extended-release tablets. 

The optimal daily dose at the end of the titration period for patients on immediate-release formulation of ropinirole was substantially lower (mean: 7 mg) compared with the dose at the end of the titration period for patients on ropinirole extended-release tablets (mean: 18 mg). In this trial, the marked difference in the final optimal dosages suggests that the higher doses afforded no additional benefit when compared with the lower doses [see Dosage and Administration (2.2)]. 

Study 4 (Fixed-Dose, Dose-Response Trial)

A double-blind, placebo-controlled, fixed-dose, parallel-group trial evaluated the dose response of ropinirole extended-release tablets without L-dopa in 186 randomized patients with early Parkinson’s disease (Hoehn & Yahr Stages I-III) over a total dosing period of 18 weeks. Patients initiated treatment with placebo or ropinirole extended-release tablets at 2 mg/day for 1 week and were either maintained at a target dose of 2 mg/day or further increased to a target dose of 4, 8, 12, or 24 mg/day over a 13-week up-titration period. The dose remained stable over an additional 4-week maintenance period, followed by a 1-week down-titration period. The primary statistical analysis of the primary efficacy endpoint was Mixed Model Repeated Measures (MMRM).

The primary efficacy endpoint was the change from baseline in UPDRS motor score at Week 4 of the maintenance period with daily doses of 2, 4, 8, 12, and 24 mg compared with placebo. At baseline, the mean UPDRS motor score ranged from approximately 21 to 25 across all groups receiving ropinirole extended-release tablets and placebo. Table 7 shows results for the primary efficacy endpoint. The greatest treatment difference (ropinirole extended-release tablets – PLACEBO) for the primary efficacy endpoint occurred with the 12-mg dose. At Week 4 of the maintenance period, the primary efficacy analysis (MMRM) did not show a significant difference between placebo (mean adjusted change: -3.98) and any dose of ropinirole extended-release tablets (mean adjusted changes ranged from -4.09 to -6.14). Data were also analyzed by nonparametric ANCOVA as pre-specified because of non-normality. This analysis and showed that there was a significant reduction from baseline in the UPDRS motor score for the group receiving ropinirole extended-release tablets 12 mg/day (P = 0.047); however, higher doses were not shown to provide additional benefit.

Table 7. Change from Baseline in Unified Parkinson’s Disease Rating Scale (UPDRS) Part III Motor Score (Primary Efficacy Endpoint) at the End of the Maintenance Period (Study 4)

a P value not adjusted for multiple comparisons. A hierarchical step-down approach for statistical testing was used starting with 12-mg dose.