A Study to Evaluate Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of BIIB054 in Japanese Participants With Parkinson's Disease

Study Overview
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Brief Summary
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The primary objective of this study is to evaluate the safety and tolerability of a range of single and 13 repeated doses of BIIB054, administered as intravenous (IV) infusion, in Japanese participants with Parkinson's disease (PD). The secondary objectives are to evaluate the immunogenicity, and serum pharmacokinetics (PK) profile of BIIB054 after single and multiple dose administration.

Official Title
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A Multicenter, Blinded, Placebo-Controlled, Randomized, Single and Multiple-Ascending Dose Study of the Safety, Tolerability, Pharmacokinetics, and Pharmacodynamics of BIIB054 in Japanese Subjects With Parkinson's Disease

Conditions
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Parkinson's Disease

Intervention / Treatment
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* Drug: BIIB054
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Key Inclusion Criteria: Diagnosed with PD within a maximum of 3 years prior to screening. Has not received levodopa or any other treatment for PD, herein referred to as symptomatic PD medication (including but, not limited to, dopamine agonists, amantadine, anticholinergics, monoamine oxidase type B (MAO-B) inhibitors, or safinamide) for at least 12 weeks prior to Day 1. Maximum total duration of prior PD regimens should not exceed 30 days. Score of less than equal to (<=) 2.5 on the Modified Hoehn and Yahr Scale. Screening dopamine transporter (DaT)/ single-photon emission computed tomography (SPECT) results consistent with neurodegenerative Parkinsonism (central reader). Key Exclusion Criteria: Presence of freezing of gait. History of or positive test result at Screening for human immunodeficiency virus (HIV) or hepatitis C virus antibody (anti-HCV). Screening value for hemoglobin less than (<)12 gram per deciliter (g/dL) for men or <11 g/dL for women. Montreal Cognitive Assessment (MoCA) score <23 or other significant cognitive impairment or clinical dementia. History of any brain surgery for PD. Participation in any passive or active immunotherapy targeting alpha-synuclein or other PD-related protein. NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.

Ages Eligible for Study
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Minimum Age: 40 Years
Maximum Age: 80 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Design Details

Primary Purpose: Treatment
Allocation: Randomized
Intervention Model: Sequential Assignment
Masking: Triple


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Cohort 1: BIIB054 Dose A<br>Participants will receive IV infusion of BIIB054 Dose A (single infusion on Day 1 followed by an observation period; with subsequent doses for 48 weeks) | Drug: BIIB054<br>* Administered as specified in the treatment arm.<br>|
| Experimental: Cohort 2: BIIB054 Dose B<br>Participants will receive IV infusion of BIIB054 Dose B (single infusion on Day 1 followed by an observation period; with subsequent doses for 48 weeks) | Drug: BIIB054<br>* Administered as specified in the treatment arm.<br>|
| Experimental: Cohort 3: BIIB054 Dose C<br>Participants will receive IV infusion of BIIB054 Dose C (single infusion on Day 1 followed by an observation period; with subsequent doses for 48 weeks) | Drug: BIIB054<br>* Administered as specified in the treatment arm.<br>|
| Placebo Comparator: Cohorts 1-3: Placebo<br>Participants will receive a single IV infusion of BIIB054 matching placebo (single infusion on Day 1 followed by an observation period; with subsequent doses for 48 weeks) | Drug: Placebo<br>* Administered as specified in the treatment arm.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Number of Participants With Adverse Events (AEs) and Serious Adverse Events (SAEs) | An AE is any untoward medical occurrence in a participant or clinical investigation participant administered a pharmaceutical product and that does not necessarily have a causal relationship with this treatment. An AE can therefore be any unfavorable and unintended sign (including an abnormal laboratory finding), symptom, or disease temporally associated with the use of a medicinal (investigational) product, whether or not related to the medicinal (investigational) product. An SAE is any untoward medical occurrence that at any dose results in death, is a life-threatening event, requires inpatient hospitalization or prolongation of existing hospitalization, results in a significant disability/incapacity or congenital anomaly, or is a medically important event. | Up to 72 Weeks | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Area Under the Serum Concentration-Time Curve From Time Zero Extrapolated to Infinite Time (AUCinf) of BIIB054 |  | Up to 24 Weeks | 
| Area Under the Curve From Time Zero to End of Dosing Interval (AUCtau) of BIIB054 |  | Up to 24 Weeks | 
| Maximum Observed Serum Concentration (Cmax) of BIIB054 |  | Up to 24 Weeks | 
| Time to Reach Maximum Observed Serum Concentration (Tmax) of BIIB054 |  | Up to 24 Weeks | 
| Terminal Elimination Half-life (t1/2) of BIIB054 |  | Up to 24 Weeks | 
| Clearance (CL) of BIIB054 |  | Up to 24 Weeks | 
| Volume of Distribution at Steady State (Vss) of BIIB054 |  | Up to 24 Weeks | 
| Accumulation Ratio of BIIB054 |  | Up to 24 Weeks | 
| Observed Concentration at the End of Dosing Interval (Ctrough) of BIIB054 |  | Up to 24 Weeks | 
| Number of Participants With Anti-BIIB054 Antibodies in Serum |  | Up to 72 Weeks |