for people ages 50-85 (full criteria)
at San Francisco, California and other locations
study started
estimated completion



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

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


Parkinsons Disease, Parkinson Disease, Prasinezumab


You can join if…

Open to people ages 50-85

  • 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

You CAN'T join if...

  • 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


  • UCSF in progress, not accepting new patients
    San Francisco California 94117 United States
  • Cedars Sinai Medical Center in progress, not accepting new patients
    Los Angeles California 90048 United States


accepting new patients at some sites,
but this study is not currently recruiting here
Start Date
Completion Date
Hoffmann-La Roche
Phase 2 Parkinson's Disease Research Study
Study Type
Expecting 575 study participants
Last Updated