A Fixed Dose, Dose Response Study for Ropinirole Prolonged Release (PR) in Patients With Early Stage Parkinson's Disease

This study is a fixed dose, dose response study to characterize the dose response for ropinirole PR in early stage PD patients (Hoehn & Yahr stages I-III). After screening and baseline assessments, subjects will be randomized to one of six final target treatment groups (placebo, 2, 4, 8, 12 or 24mg/day ropinirole PR). The study will consist of a screening period, an up-titration period, a maintenance period, a down titration period and a follow up period. This study utilizes change from baseline in the UPDRS motor score as the primary endpoint, in line with that used in the ropinirole PR monotherapy pivotal study (SK&F101468/168). Clinical review of the primary and secondary endpoints will be performed in order to establish the lowest maximally effective therapeutic dose.