BTRX-246040 Study in Participants With Parkinson's Disease With Motor Fluctuations

Inclusion Criteria

• Diagnosed with Parkinson's disease (PD), consistent with the United Kingdom PD Society Brain Bank Criteria for the Diagnosis of PD
• Men or women ≥ 30 years old and ≤ 76 years old
• Female participants must be either surgically sterilized or 2 years post menopausal at screening
• Modified Hoehn and Yahr Staging ≤ 3 in the ON state
• Montreal Cognitive Assessment (MoCA) Score ≥ 26
• Currently has a clear and decisive response to levodopa, and receiving a stable dose of levodopa (at least 4 doses per day of levodopa or ≥ 3 doses per day of RytaryTM (carbidopa and levodopa) extended-release capsules for at least 4 weeks prior to screening)
• Experiencing motor fluctuations during waking hours with at least 2 hours of OFF periods each day, including predictable early morning OFF periods, based on participant assessment
• Able to participate in the study in the practically defined OFF state
• All anti-parkinsonian medications maintained at a stable dose for at least 4 weeks prior to the initial Screening Visit with the exception of monoamine oxidase B (MAO-B) inhibitors, which must be maintained at a stable level for at least 8 weeks prior to the screening visit
• Approved by a central Enrollment Authorization Committee as meeting entry criteria and being a suitable candidate for the study
• Male participants agree to use a reliable method of birth control during the study and for at least 90 days following the last dose of BTRX-246040 or placebo
• Informed and given ample time and opportunity to think about his/her participation in this study and has given his/her written informed consent on an Institutional Review Board (IRB) or Independent Ethics Committee (IEC) approved consent form
• Judged to be reliable and able to keep all appointments for clinic visits, tests, and procedures, including venipuncture, and examinations required by the protocol

Exclusion Criteria

• Diagnosis of secondary or an atypical Parkinsonian syndrome
• Severe disabling dyskinesia
• Clinically significant psychosis or hallucinations or history of psychosis in past 6 months
• History of previous neurosurgery for PD
• Currently or previously on Duopa/Duodopa
• Currently taking apomorphine
• Has a diagnosis or history of a substance related disorder per Diagnostic and Statistical Manual of Mental Disorders V edition (DSM-V) criteria (including alcohol but excluding nicotine and caffeine), during the 12 months prior to the Screening Visit
• Medical or recreational use of marijuana in the 6 months prior to the Screening Visit
• Has tested positive at the Screening Visit for drugs of abuse (opiates, cannabinoids, methadone, cocaine, and amphetamines [including ecstasy])
• Active suicidal ideation within 1 year prior to the Screening Visit as evidenced by answering "yes" to Questions 4 or 5 on the suicidal ideation portion of the Columbia- Suicide Severity Rating Scale (C-SSRS) or attempted suicide within the last 1 year
• Current major depressive episode or a Beck Depression Inventory-II (BDI-II) score above 19. Participants receiving treatment for depression with antidepressants may be enrolled if they have been on a stable daily dose for at least 8 weeks before the Screening Visit and are clinically stable in the opinion of the Principal Investigator
• Currently or within 8 weeks of screening receiving bupropion
• Exposure to neuroleptics (antipsychotic drugs) for more than 1 month within the past 2 years, or any exposure within the past year
• Any malignancy in the 5 years prior to randomization (excluding successfully treated basal cell carcinoma of the skin or cervical carcinoma in situ)
• Current or previous diagnosis of malignant melanoma or the presence of any suspicious skin lesion based on physical exam findings
• Any other clinically significant medical condition or circumstance prior to randomization that, in the opinion of the Investigator, could affect participant safety, preclude evaluation of response, interfere with t