This is a Phase 2 study in people with Parkinson's disease who experience motor fluctuations while taking levodopa. The study will evaluate how effective two different doses of the study drug AP-472 are when added to levodopa treatment, compared with a placebo.
The study will last about 12 weeks. Participants will be randomly assigned to receive one of the two doses of AP-472 or a placebo. Neither the participants nor the study staff will know which treatment is given.
The study includes a screening period, a 4-week period during which Parkinson's medications must remain stable, and an 8-week treatment period. During the treatment period, limited adjustments to levodopa are allowed if needed.
Be a man or woman between 30 and 80 years of age at the time of screening.
Have a diagnosis of Parkinson's disease, confirmed using standard medical criteria, including slowness of movement and symptoms that affect one side of the body more than the other.
Have mild to moderate Parkinson's disease, defined as stage 3 or lower on the Hoehn and Yahr scale when medications are working ("ON" state).
Experience an average of at least 3 hours of OFF time per day, based on home symptom diaries, with at least 2.5 hours of OFF time each day during the baseline period.
Have a form of parkinsonism that is not typical Parkinson's disease, such as secondary or atypical parkinsonism.
Have previously received, or plan to receive during the study, advanced Parkinson's therapies such as continuous levodopa or dopamine delivery systems, or Parkinson's disease-related brain surgery.
Have dyskinesias (involuntary movements) that are severe enough, in the study doctor's opinion, to interfere with participation.
Have a history of only certain types of dyskinesias (such as OFF-state, diphasic, myoclonic, or dystonic dyskinesias) without typical peak-dose dyskinesias.