For Healthcare Professionals

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


About the study

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.

Who can take part

You may be eligible to participate in the study if you meet the following criteria:


Inclusion Criteria:

  1. 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
  2. On symptomatic PD medication, with stable doses for at least 3 months prior to baseline
  3. A diagnosis of PD for at least 3 months to maximum 3 years at screening
  4. MDS-UPDRS Part IV score of 0 at screening and prior to randomization
  5. Hoehn and Yahr (H&Y) Stage I or II in OFF medication state at screening and prior to randomization
  6. Dopamine transporter imaging with single photon emission computed tomography (DaT-SPECT) imaging consistent with dopamine transporter deficit, as assessed by the central reader
  7. No anticipated changes in PD medication from baseline throughout the study duration based on clinical status during screening
  8. Willingness and ability to use a smartphone application to measure PD-related symptoms for the duration of the study
  9. Willingness and ability to wear a smartwatch to measure PD-related motor signs


Exclusion Criteria:

  1. Medical history indicating a Parkinsonian syndrome other than idiopathic PD
  2. Diagnosis of PD dementia
  3. Diagnosis of a significant neurologic disease other than PD
  4. Within the last year, unstable or clinically significant cardiovascular disease
  5. Uncontrolled hypertension
  6. Drug and/or alcohol abuse within 12 months prior to screening, in the investigator's judgment (Nicotine is allowed, Marijuana use is not allowed)
  7. Clinically significant abnormalities in laboratory test results at the screening visit, including hepatic and renal panels, complete blood count, chemistry panel and urinalysis
  8. Allergy to any of the components of prasinezumab, a known hypersensitivity, or a previous IRR following administration of any other monoclonal antibody
  9. Any contraindications to obtaining a brain magnetic resonance imaging (MRI)
  10. Any contraindications to DaT-SPECT imaging

pin location

Study Locations

Enter your ZIP code/Postal code/PIN code to locate study sites near you:

How to Apply

Contact the study center to learn if this study is a good match for you.

Study’s details


Parkinsons Disease

Age (in years)

50 - 85


Phase 2

Participants needed


Est. Completion Date

Nov 27, 2026

Treatment type



Hoffmann-La Roche identifier


Study number


Understanding Clinical Trials

Get answers to your questions about clinical trials.What is a clinical research?What does taking part in clinical trials involve?What should I ask the trial doctor?


Sign up to save your favorites, 
receive newsletters, resources, and alerts 
about clinical trials related to your conditions of interest.