for people ages 30-80 (full criteria)
at San Francisco, California and other locations
study started
completion around
Principal Investigator
by Marta San Luciano Palenzuela
Headshot of Marta San Luciano Palenzuela
Marta San Luciano Palenzuela



In this study, researchers will learn more about a study drug called BIIB122 in participants with early-stage Parkinson's disease (PD). In this study:

  • Participants will take 225 milligrams (mg) of BIIB122 or a placebo as tablets by mouth. A placebo looks like the study drug but has no real medicine in it.
  • Participants will take BIIB122 or placebo 1 time a day for up to a minimum of 48 weeks and a maximum of 144 weeks.
  • Certain medications for PD will be allowed at enrollment for a subset of participants.
  • Participants will have to visit at 2-week intervals between baseline and week 12 and at 4-week intervals between week 12 and week 48 and at 12 week intervals between week 48 and week 144. The main question researchers are trying to answer is if taking BIIB122 slows the worsening of symptoms more than placebo in the early stages of PD.

To help answer this question, researchers will use a questionnaire called the Movement Disorder Society-Unified Parkinson's Disease Rating Scale, also known as the MDS-UPDRS. Researchers will use the MDS-UPDRS to learn about participant PD symptoms and how they affect their daily life. Researchers will also learn more about the safety of BIIB122.

Official Title

A Phase 2b, Multicenter, Randomized, Double-Blind, Placebo-Controlled Study to Determine the Efficacy and Safety of BIIB122 in Participants With Parkinson's Disease


BIIB122 is an investigational central nervous system-penetrant small molecule inhibitor of leucine-rich repeat kinase 2 (LRRK2). Participants who completed the early termination (ET) visit of the study 283PD302 (NCT05418673) would be eligible for screening of this study and if enrolled, these participants are not eligible for the sub studies of 283PD201.


Parkinson Disease, Early-stage Parkinson Disease, BIIB122, BIIB122 225 mg


You can join if…

Open to people ages 30-80

  • Clinical diagnosis of PD meeting the Movement Disorder Society Clinical Diagnostic Criteria within 2 years of the Screening Visit, inclusive, and at least 30 years of age at the time of diagnosis
  • Modified Hoehn and Yahr scale stages 1 to 2 (in OFF state), inclusive, at screening
  • MDS-UPDRS Parts II and III (in OFF state) combined score less than or equal to (≤)40 at screening

You CAN'T join if...

  • Clinically significant neurological disorder other than PD, including but not limited to stroke, dementia, or seizure, within 5 years of screening visit, in the opinion of the Investigator
  • Clinical evidence of atypical parkinsonism (e.g., multiple-system atrophy or progressive supranuclear palsy) or evidence of drug-induced parkinsonism.
  • Montreal Cognitive Assessment (MoCA) score <24 at the screening visit.

    NOTE: Other protocol defined Inclusion/Exclusion criteria may apply.


  • UCSF (UCSF) accepting new patients
    San Francisco California 94143 United States
  • Cedars Sinai accepting new patients
    Los Angeles California 90048 United States
  • SC3 Research Group Inc. accepting new patients
    Pasadena California 91105 United States

Lead Scientist at UCSF

  • Marta San Luciano Palenzuela
    Dr. Marta San Luciano specializes in diagnosing and managing movement disorders, including Parkinson's disease, dystonia, tremor and myoclonus, in both children and adults.


accepting new patients
Start Date
Completion Date
Click here to learn more about this trial, visit our study website.
Phase 2 Parkinson's Disease Research Study
Study Type
Expecting 640 study participants
Last Updated