A Study to Evaluate the Safety and Tolerability of SAGE-718 in Participants With Parkinson's Disease Mild Cognitive Impairment (PD-MCI)

An Open-Label Evaluation of the Safety and Tolerability of SAGE-718 in Participants With Parkinson's Disease Mild Cognitive Impairment

The primary purpose of this two-part study was to evaluate the safety and tolerability of SAGE-718 and its effects on cognitive, neuropsychiatric, and motor symptoms in participants with Parkinson's disease mild cognitive impairment (PD-MCI).

Inclusion Criteria:

1. Meet the following criteria for PD-MCI: Have a confirmed diagnosis of idiopathic PD according to 2015 Movement Disorder Society (MDS) clinical diagnostic criteria; Meet MDS Task Force Criteria for MCI in PD.
2. Have a score of 20 to 25 (inclusive) on the Montreal Cognitive Assessment (MoCA) at Screening.
3. Meet criteria for Hoehn & Yahr Stage I to III (mild to moderate motor severity) at Screening.
4. Have stable motor symptoms for at least 4 weeks prior to screening, in the opinion of the investigator.

Exclusion Criteria:

1. Have a diagnosis of dementia of any etiology, including but not limited to: Dementia associated with PD (probable or possible), Dementia with Lewy Bodies, Alzheimer's Dementia, and Vascular Dementia.
2. Have any indication of parkinsonism other than idiopathic PD.
3. In the opinion of the investigator, be experiencing unpredictable fluctuations in motor and/or nonmotor symptoms associated with PD.
4. Have an ongoing central nervous system condition other than idiopathic PD, including active neurologic and/or nonremitted psychiatric disorders, in the opinion of the investigator.
5. Have a history of brain surgery, deep brain stimulation, a significant head injury causing loss of consciousness greater than 30 minutes, or hospitalization due to a brain injury.
6. Have experienced significant psychotic symptoms within the past 3 months, including those associated with PD medications, as determined by the investigator.