Skip to main content
OpenTrials
Recruiting

NCT Number: NCT07174310

A Study to Evaluate the Efficacy and Safety of Intravenous (IV) Prasinezumab in Participants With Early-Stage Parkinson's Disease

The purpose of this study is to evaluate the efficacy, safety, and pharmacokinetics (PK) of prasinezumab compared with placebo in participants with early-stage Parkinson's disease (PD) on stable symptomatic monotherapy with levodopa.

Recruiting

Interested in participating?

Request Info

Key information

Conditions

Parkinson's Disease Basal Ganglia Diseases Brain Diseases Central Nervous System Diseases Movement Disorders Nervous System Diseases Neurodegenerative Diseases Parkinson Disease Parkinsonian Disorders Synucleinopathies

Age range

50 year–85 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 3

Primary location

Southern Neurology, Kogarah, New South Wales, Australia

Loading trial locations.

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • 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
  • Has received monotherapy treatment
  • An MDS-UPDRS Part IV score of 0 at screening and prior to randomization
  • Hoehn and Yahr (H&Y) Stage 1 or 2 off medication at screening and prior to randomization
  • Agreement to adhere to the contraception requirements

Exclusion criteria

  • Pregnant or breastfeeding, or intention of becoming pregnant during the study or within the time frame in which contraception is required
  • Medical history indicating a parkinsonian syndrome other than idiopathic PD
  • Diagnosis of a significant neurologic disease other than PD
  • Chronic uncontrolled hypertension

Treatment and study plan

Prasinezumab

Drug

Participants will receive Prasinezumab as an IV Infusion as per the schedule mentioned in the protocol.

Placebo

Drug

Participants will receive Placebo as an IV Infusion per the schedule mentioned in the protocol

Primary outcomes

  1. Time to Confirmed Motor Progression Event on Movement Disorder Society - Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III Score

    Time frame: Up to at least Week 104

Secondary outcomes

  1. Change From Baseline in Motor Function as Measured by the MDS-UPDRS Part III off Medication Score

    Time frame: Baseline, Week 104

  2. Time to Worsening of Participants Motor Function as Reported by the Participant in the Presence of a Confirmed Motor Progression Event

    Time frame: Up to at least Week 104

  3. Time to Meaningful Worsening in Clinician Global Impression of Change (CGI-C), Overall Disease Subscale

    Time frame: Up to at least Week 104

  4. Time to increase in Levodopa Equivalent Daily Dose (LEDD)

    Time frame: Up to at least Week 104

  5. Percentage of Participants With Treatment Emergent Adverse Events (TEAEs)

    Time frame: From Baseline up to 70 days after the final study dose (up to at least Week 104)

  6. Percentage of Participants With Adverse Events of Special Interest (AESI)

    Time frame: From Baseline up to 70 days after the final study dose (up to at least Week 104)

  7. Percentage of Participants With Infusion Related Reactions (IRRs)

    Time frame: From Baseline up to 70 days after the final study dose (up to at least Week 104)

  8. Percentage of Participants With Suicidal Ideation, as Measured by the Columbia-Suicide Severity Rating Scale (C-SSRS)

    Time frame: From Baseline up to 70 days after the final study dose (up to at least Week 104)

  9. Serum Concentration of Prasinezumab

    Time frame: Predose and postdose at Baseline, Week 1, 4, 12, 24, 36, 52, 76, and after week 76 every 12 weeks thereafter until end of study (up to at least Week 104)

  10. Percentage of Participants With Anti-drug Antibodies (ADAs) Against Prasinezumab at Baseline

    Time frame: At Baseline

  11. Percentage of Participants With ADAs Against Prasinezumab During the Study

    Time frame: From Baseline up to 70 days after the final study dose (up to at least Week 104)

Study contacts

Contact information is provided by the study sponsor or research team.

Fastest response: use the inquiry form. https://www.gene.com/contact-us/submit-medical-inquiry

CONTACT

Reference Study ID Number: BN44715 https://forpatients.roche.com/ No attachments to email below.

CONTACT

[email protected]

888-662-6728 (U.S. and Canada)

Sponsors and collaborators

Lead sponsor

Hoffmann-La Roche

Industry

Collaborators

  • Prothena Biosciences Limited

Registry information

Official study title

A 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

Acronym: PARAISO

Important dates

Study start
2025
Primary completion
2029
Study completion
2031
First posted
Sep 15, 2025
Registry last updated
Jul 6, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

Related clinical trials

Published trials that share one or more normalized conditions with this study.