Open-label Trial in Parkinson's Disease (PD)

Key Inclusion Criteria:

Rollover participants are eligible for the study if they met the following inclusion criteria:

1. Participants who complete the 27-week double-blind Treatment Period of Trial CVL-751-PD-001 (NCT04201093) or Trial CVL-751 PD-003 (NCT04542499) or the 27-week double-blind Treatment Period and 10-day Safety/Withdrawal Assessment Period of Trial CVL-751-PD-002 (NCT04223193) and enter this trial within 72 hours after completing the last trial visit in the double-blind trial. Rollover participants from Trial CVL-751-PD-003 must continue to use levodopa/carbidopa (or levodopa/benserazide) for the duration of the trial.
2. Sexually active men or women of childbearing potential must agree to use acceptable (at minimum) or highly effective birth control, or remain abstinent during the trial and for 4 weeks after the last dose of trial treatment.
3. Participants who are capable of giving signed informed consent, which includes compliance with the requirements and restrictions listed in the ICF and in the protocol.
4. Participants who are willing and able to refrain from any PD medications that are not permitted by the protocol (including dopaminergic agents) throughout participation in the trial.
5. Participant who, in the judgement of the investigator, demonstrated adequate compliance with the IMP and protocol requirements in the double-blind trial.

Key Exclusion criteria:

Rollover participants are excluded from the trial if any of the following met:

1. Participants who do not enroll in this open-label trial within 72 hours after completing the last trial visit in the double-blind trial
2. Participants who answer "yes" on the C-SSRS Suicidal Ideation Item 4 or Item 5 (Active Suicidal Ideation with Some Intent to Act, Without Specific Plan, or Active Suicidal Ideation with Specific Plan and Intent) and whose most recent episode meeting the criteria for C-SSRS Item 4 or Item 5 occurred within the last 6 months, OR Participants who answer "yes" on any of the 5 C-SSRS Suicidal Behavior Items (actual attempt, interrupted attempt, aborted attempt, preparatory acts, or behavior) and whose most recent episode meeting the criteria for any of these 5 C-SSRS Suicidal Behavior Items occurred within the last 2 years, OR Participants who, in the opinion of the investigator, present a serious risk of suicide.
3. Participants who had previously been enrolled in this open-label trial and had subsequently withdrawn.