An Exploratory Study of XP21279 (With Lodosyn®) and Sinemet® in Parkinson's Disease Subjects

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®).

Inclusion criteria

• Subjects with a clinical diagnosis of idiopathic Parkinson's disease, confirmed by the presence of at least two cardinal signs of the disease (resting tremor, bradykinesia, rigidity).
• Subjects must have predictable motor fluctuations of the wearing off type, defined by wearing off in at least 50% of inter-dose intervals between the first and the last daily doses as recorded on the on/off diary over 3 days (Days -4 to -2) in the Screening Period.
• Subjects must be on stable TID or QID Sinemet® or carbidopa/levodopa regimens from morning through early evening, with a total daily dose ranging from 400 mg to 1000 mg of levodopa, for at least 1 week prior to Screening.

Exclusion criteria

• History, signs, or symptoms suggesting the diagnosis of secondary or atypical Parkinsonism.
• Subject has greater than or equal to moderately disabling dyskinesias for greater than 25% of the waking day as assessed by a score of 2 or more on item 32 and a score of 2 or more on item 33 on the UPDRS at Screening.
• Subjects who are dosing with Sinemet® or carbidopa/levodopa during the night time.
• Subjects who have significant neurological symptoms not accounted for by Parkinson's disease.
• Subjects who are taking concomitantly COMT inhibitors (i.e., entacapone or tolcapone) or treated with Stalevo®, Sinemet® CR, or Madopar®/Prolopa® (levodopa/benserazide).