Recruiting

PARAISOIntravenous Prasinezumab for Early-Stage Parkinson's Disease

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What is being tested

Prasinezumab

+ Placebo

Drug
Who is being recruted

Synucleinopathies+6

+ Basal Ganglia Diseases

+ Brain Diseases

From 50 to 85 Years
+10 Eligibility Criteria
See all eligibility criteria
How is the trial designed

Treatment Study

Phase 3
Interventional
Study Start: November 2025
See protocol details

Summary

Principal SponsorHoffmann-La Roche
Study ContactReference Study ID Number: BN44715 https://forpatients.roche.com/
Last updated: February 10, 2026
Sourced from a government-validated database.Claim as a partner

Study start date: November 24, 2025

Actual date on which the first participant was enrolled.

This clinical trial focuses on understanding how effective and safe a treatment called prasinezumab is for people who have early-stage Parkinson's disease. Parkinson's disease is a condition that affects movement and often starts with mild symptoms like a slight tremor. The study targets those who are already taking a stable dose of a common Parkinson's medication called levodopa. The goal is to see if prasinezumab can improve their symptoms or slow the progression of the disease. This research is important because finding better treatments can significantly enhance the quality of life for those living with Parkinson's. Participants in this study will receive prasinezumab through an intravenous (IV) infusion, meaning the medicine will be given directly into a vein. Some participants will receive a placebo, which is a substance with no active drug, to compare the effects. The study will monitor how prasinezumab affects the body and its safety for patients. Researchers will evaluate whether the treatment helps with Parkinson's symptoms and assess its overall safety. By comparing prasinezumab to a placebo, the study aims to provide clear insights into its potential benefits and any risks involved.

Official TitleA Phase III, Randomized, Double-Blind, Placebo-Controlled, Multicenter Study to Evaluate the Efficacy and Safety of Intravenous Prasinezumab in Participants With Early-Stage Parkinson's Disease
NCT07174310
Principal SponsorHoffmann-La Roche
Study ContactReference Study ID Number: BN44715 https://forpatients.roche.com/
Last updated: February 10, 2026
Sourced from a government-validated database.Claim as a partner

Protocol

This section provides details of the study plan, including how the study is designed and what the study is measuring.
Design Details

900 patients to be enrolled

Total number of participants that the clinical trial aims to recruit.

Treatment Study

These studies test new ways to treat a disease, condition, or health issue. The goal is to see if a new drug, therapy, or approach works better or has fewer side effects than existing options.



Eligibility

Researchers look for people who fit a certain description, called eligibility criteria: person's general health condition or prior treatments.
Conditions
Criteria

Any sex

Biological sex of participants that are eligible to enroll.

From 50 to 85 Years

Range of ages for which participants are eligible to join.

Healthy volunteers not allowed

If individuals who are healthy and do not have the condition being studied can participate.

Conditions

Pathology

SynucleinopathiesBasal Ganglia DiseasesBrain DiseasesCentral Nervous System DiseasesMovement DisordersNervous System DiseasesParkinson DiseaseNeurodegenerative DiseasesParkinsonian Disorders

Criteria

6 inclusion criteria required to participate
Body weight within 40-110 kilograms (kg) (88-242 pounds [lbs]) and a body mass index within the range 18-34 kg/m2

Diagnosis of idiopathic PD based on Movement Disorder Society (MDS) criteria

Agreement to adhere to the contraception requirements

Hoehn and Yahr (H&Y) Stage 1 or 2 off medication at screening and prior to randomization

Show More Criteria

4 exclusion criteria prevent from participating
Pregnant or breastfeeding, or intention of becoming pregnant during the study or within the time frame in which contraception is required

Diagnosis of a significant neurologic disease other than PD

Medical history indicating a parkinsonian syndrome other than idiopathic PD

Chronic uncontrolled hypertension

Study Plan

Find out more about all the medication administered in this study, their detailed description and what they involve.
Treatment Groups
Study Objectives

2 intervention groups are designated in this study

This study does not include a placebo group 

Treatment Groups

Group I

Experimental
Participants will receive Prasinezumab as an IV infusion in the double blind treatment period. Upon completion, eligible participants will enter into the Open Label Extension (OLE) phase.

Group II

Experimental
Participants will receive placebo as an IV Infusion.

Study Objectives

Primary Objectives

Secondary Objectives

Study Centers

These are the hospitals, clinics, or research facilities where the trial is being conducted. You can find the location closest to you and its status.

This study has 38 locations

Recruiting

Neurology Center of North Orange County

Fullerton, United StatesOpen Neurology Center of North Orange County in Google Maps
Recruiting

Keck School of Medicine of USC

Los Angeles, United States
Recruiting

Profound Research LLC at The Neurology Center of Southern California

Pasadena, United States
Recruiting

UCSF Weill Institute for Neurosciences

San Francisco, United States
Recruiting
38 Study Centers