A Phase III, Randomised, Double-blind, Placebo-controlled, Parallel Group Study of Six Months Treatment With Ropinirole PR as Adjunctive Therapy in Patients With Parkinson's Disease Who Are Not Optimally Controlled on L-Dopa

This is a phase III, multicenter, randomized, double-blind, parallel group, placebo-controlled study to compare the efficacy of 6-months therapy of ropinirole Prolonged Release (PR) with that of placebo as adjunctive therapy to L-dopa in Parkinson's disease patients not optimally controlled on L-dopa. This study will be conducted in China. Subjects will have total 14 visits over the 26 week duration of the study. Following screening, eligible subjects will receive study medication during the fourteen day placebo run-in period which they will be instructed to take in addition to their background L-dopa. If subjects are still eligible at the end of the placebo run-in period they will be randomized (1:1) to receive once daily doses of ropinirole PR or identical appearing placebo tablets. Dosing will start at 2 mg ropinirole PR, or placebo equivalent. During the 24 week treatment phase, the subjects dose will be adjusted according to the recommended schedule to achieve symptomatic control. All subjects must be titrated to a minimum dose of 6 mg/day. If sufficient symptomatic control is not achieved or maintained at a dose of 6mg/day of ropinirole PR, the daily dose should be increased by 2mg at weekly or longer intervals up to a dose of 8mg/day.If sufficient symptomatic control is still not achieved or maintained at a dose of 8mg/day of ropinirole PR, the daily dose should be increased by 4mg at two weekly or longer intervals. Further dose titration should not be conducted within the final 8 weeks of the treatment phase. The maximum recommended daily dose is 24mg. The planned reduction in L-dopa dose will begin once subjects are titrated to Dose Level 4 or Dose Level 5 of study medication. For each increase in study medication, there will be a corresponding decrease in L-dopa. If loss of symptom control occurs with the reduction in the background L-dopa dose, the dose of study medication should be increased to the next higher dose level with no adjustment in the dose