PF 06412562 in Subjects With Advanced Stage Parkinson's Disease

The investigators are conducting a randomized, double-blind, carbidopa/levodopa-controlled crossover safety, tolerability, and efficacy study of the investigational compound, PF-06412562, in advanced Parkinson's patients. The primary purpose of this study is to test the safety and tolerability of the investigational drug PF-06412562 compared to the current medical standard of care medication for Parkinson's disease, carbidopa/levodopa, in these patients. This secondary purpose of this research is to find out if the investigational drug PF-06412562 can help improve the motor (movement) function, alertness, and cognitive (thinking) skills of people who are considered to be in the advanced-stage of Parkinson's disease. This study will inform the field as to whether PF-06412562 is safe and well-tolerated in advanced Parkinson's patients, and also may provide preliminary data on its efficacy in several domains.