A Study to Evaluate the Efficacy and Safety of Intravenous Prasinezumab in Participants With Early Parkinson's Disease

Study Overview
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Brief Summary
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This is a multicenter, randomized, double-blind, placebo-controlled study that will evaluate the efficacy and safety of intravenous (IV) prasinezumab versus placebo in participants with Early Parkinson's Disease (PD) who are on stable symptomatic PD medication.

Official Title
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A Phase IIB, Randomized, Double-Blind, Placebo-Controlled, Multicenter Study to Evaluate the Efficacy and Safety of Intravenous Prasinezumab in Participants With Early Parkinson's Disease

Conditions
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Parkinsons Disease

Intervention / Treatment
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* Drug: Prasinezumab
* Drug: Placebo


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Diagnosis of idiopathic PD based on MDS criteria with bradykinesia plus one of the other cardinal signs of PD (resting tremor, rigidity), without any other known or suspected cause of parkinsonism On symptomatic PD medication, with stable doses for at least 3 months prior to baseline A diagnosis of PD for at least 3 months to maximum 3 years at screening MDS-UPDRS Part IV score of 0 at screening and prior to randomization Hoehn and Yahr (H&Y) Stage I or II in OFF medication state at screening and prior to randomization Dopamine transporter imaging with single photon emission computed tomography (DaT-SPECT) imaging consistent with dopamine transporter deficit, as assessed by the central reader No anticipated changes in PD medication from baseline throughout the study duration based on clinical status during screening Willingness and ability to use a smartphone application to measure PD-related symptoms for the duration of the study Willingness and ability to wear a smartwatch to measure PD-related motor signs Exclusion Criteria: Medical history indicating a Parkinsonian syndrome other than idiopathic PD Diagnosis of PD dementia Diagnosis of a significant neurologic disease other than PD Within the last year, unstable or clinically significant cardiovascular disease Uncontrolled hypertension Drug and/or alcohol abuse within 12 months prior to screening, in the investigator's judgment (Nicotine is allowed, Marijuana use is not allowed) Clinically significant abnormalities in laboratory test results at the screening visit, including hepatic and renal panels, complete blood count, chemistry panel and urinalysis Allergy to any of the components of prasinezumab, a known hypersensitivity, or a previous IRR following administration of any other monoclonal antibody Any contraindications to obtaining a brain magnetic resonance imaging (MRI) Any contraindications to DaT-SPECT imaging

Ages Eligible for Study
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Minimum Age: 50 Years
Maximum Age: 85 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: Parallel Assignment
Masking: Double


Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Experimental: Prasinezumab<br>Participants will receive an IV infusion of prasinezumab every 4 weeks (Q4W). Participants will enter into the optional Open Label Extension (OLE) once the double-blind treatment period has completed. | Drug: Prasinezumab<br>* Prasinezumab will be administered as an IV infusion to participants Q4W.<br>|
| Placebo Comparator: Placebo<br>Participants will receive placebo as an IV infusion Q4W. | Drug: Placebo<br>* Prasinezumab placebo will be administered to participants.<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time to Confirmed Motor Progression Event |  | From baseline until 28 days after final dose of study treatment | 
| OLE: Percentage of Participants With Adverse Events (AEs) and Serious AEs (SAEs) |  | From baseline until 70 days after final dose of study treatment | 
| OLE: Number of Participants with Adverse Events of Special Interest (AESI) |  | From baseline until 70 days after final dose of study treatment | 
| OLE: Number of Participants with Infusion Related Reactions (IRRs) |  | From baseline until 70 days after final dose of study treatment | 
| OLE: Change from Baseline in Suicidal Ideation, as Measured by the Columbia-Suicide Severity Rating Scale (C-SSRS) |  | From baseline until 70 days after final dose of study treatment | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Time-to-worsening of Participants Motor Function as Reported by the Participant in Movement Disorder Society - Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part II and in the Presence of a Confirmed Motor Progression Event |  | From baseline until 28 days after final dose of study treatment | 
| Time to Meaningful Worsening in Patient Global Impression of Change (PGI-C, Overall Disease Subscale) |  | From baseline until 28 days after final dose of study treatment | 
| Time to Meanaingful Worsening in Clinician Global Impression of Change (CGI-C, Overall Disease Subscale) |  | From baseline until 28 days after final dose of study treatment | 
| Time to Onset of Motor Complications as Assessed Through MDS-UPDRS Part IV |  | From baseline until 28 days after final dose of study treatment | 
| Change in Motor Function from Baseline to Week 76, as Measured by the MDS-UPDRS Part III Score |  | From baseline to Week 76 | 
| Change in Bradykinesia and Rigidity from Baseline to Week 76, as Measured by the MDS-UPDRS Part III Bradykinesia and Rigidity Subscore |  | From baseline to Week 76 | 
| Percentage of Participants With AEs and SAEs |  | From baseline until 70 days after final dose of study treatment | 
| Number of Participants with AESI |  | From baseline until 70 days after final dose of study treatment | 
| Number of Participants with IRRs |  | From baseline until 70 days after final dose of study treatment | 
| Change from Baseline in Suicidal Ideation, as Measured by the C-SSRS |  | From baseline until 28 days after final dose of study treatment | 
| Serum Concentration of Prasinezumab |  | From weeks 1, 2, 4, 8, 12, 24, 36, 52, 64, 76 and after week 76 every 12 weeks therafter until end of study (approximately 28 days after the final dose) | 
| Percentage of Participants with Anti-drug Antibodies (ADAs) Against Prasinezumab at Baseline |  | At Baseline | 
| Percentage of Participants with ADAs Against Prasinezumab During the Study |  | Up to end of study visit (approximately 76 weeks) |