The purpose of this study is to evaluate the safety, tolerability, pharmacokinetics, and pharmacodynamics of multiple oral doses of DNL151 in subjects with Parkinson's disease.

This study was previously posted by Denali Therapeutics. In July, 2022, sponsorship of the trial was transferred to Biogen.

Key Inclusion Criteria:

• Body mass index (BMI) between 18 and 35.0 kg/m2, inclusive
• Clinical diagnosis of Parkinson's disease meeting UK Brain Bank criteria and H&Y Stage I, II, or III.
• Able to hold Parkinson's disease medications 8 hours (overnight) prior to specific study assessments

Key Exclusion Criteria:

• Any history of clinically significant asthma, chronic obstructive pulmonary disease, or emphysema within 5 years of screening, or other clinically significant pulmonary disease within 6 months of screening
• Abnormal Vitals including Respiratory Rate, Body Temperature, Blood Pressure, and Pulse Rate
• Pulmonary Function Tests (PFTs) (FVC <60% predicted, FEV1 <50% predicted, FEV1:FVC ratio <0.6, DLCO <70% predicted)
• Clinically significant neurologic disorder other than Parkinson's disease, including history of stroke within 12 months of screening, cognitive impairment, seizure within 5 years of screening, or head trauma with loss of consciousness within 6 months of screening
• Montreal Cognitive Assessment (MoCA) score of <24 at screening

NOTE: Other protocol defined Inclusion/Exclusion criteria may apply

In accordance with Biogen's Clinical Trial Transparency and Data Sharing Policy on https://www.biogentrialtransparency.com/