This is a Phase 1/Phase 2 multiple-dose, multi-center, open-label, two period sequential-treatment study in subjects with Parkinson's disease to assess the pharmacokinetics, pharmacodynamics, and safety of XP21279 sustained release formulation \[administered with Lodosyn® (carbidopa)\] and Sinemet® tablets in subjects with Parkinson's disease and to explore dose correspondence between XP21279 and Sinemet® to guide dose selection for future studies in the target population (subjects with Parkinson's disease with motor fluctuations on Sinemet®).
