Prasinezumab for Parkinson's Disease

(PARAISO Trial)

Recruiting at 1 trial location

Overseen By Reference Study ID Number: BN44715 https://forpatients.roche.com/

Age: 18+

Sex: Any

Trial Phase: Phase 3

Sponsor: Hoffmann-La Roche

Must be taking: Levodopa

Disqualifiers: Pregnancy, Other neurologic disease, others

No Placebo Group All trial participants will receive the active study treatment (no placebo)

Pivotal Trial (Near Approval) This treatment is in the last trial phase before FDA approval

Prior Safety Data This treatment has passed at least one previous human trial

Compensation: Varies

Number of Visits: Unknown

Duration: 24 weeks

900 Participants Needed

What You Need to Know Before You Apply

What is the purpose of this trial?

This trial examines how well the drug prasinezumab works for people with early-stage Parkinson's disease. Researchers aim to determine if it alleviates symptoms, ensures safety, and how the body processes it compared to a placebo (a substance with no active treatment). The trial targets individuals who have been taking only levodopa and have mild symptoms that do not significantly interfere with daily life. Those managing Parkinson's with just levodopa and meeting the criteria might consider this trial as an option. As a Phase 3 trial, it represents the final step before FDA approval, offering participants a chance to contribute to potentially groundbreaking treatment advancements.

Do I need to stop my current medications for this trial?

The trial requires participants to be on a stable dose of levodopa, a common Parkinson's medication, so you won't need to stop taking it. However, the protocol doesn't specify about other medications, so it's best to discuss your current medications with the trial team.

Is there any evidence suggesting that prasinezumab is likely to be safe for humans?

Research has shown that prasinezumab is generally safe for people with early-stage Parkinson's disease. Studies have not identified any new safety issues with this treatment. Prasinezumab has undergone extensive testing, and participants did not experience unexpected side effects.

In earlier studies, prasinezumab was tested for two years, and the results suggested it might slow the progression of movement problems. This is encouraging because it indicates the treatment could help with symptoms and is safe for long-term use.

Overall, the treatment appears safe based on the current evidence. This should reassure those considering joining the trial. ^{1 2 3 4 5}

Why do researchers think this study treatment might be promising for Parkinson's disease?

Most treatments for Parkinson's Disease focus on managing symptoms through dopamine replacement, like Levodopa. But Prasinezumab works differently, targeting the buildup of alpha-synuclein, a protein believed to play a key role in the progression of Parkinson's. Researchers are excited because this approach could potentially slow down the disease itself, not just alleviate symptoms. This new mechanism of action offers hope for modifying the disease process, setting it apart from current therapies.

What evidence suggests that prasinezumab might be an effective treatment for Parkinson's disease?

Research shows that prasinezumab, which participants in this trial may receive, might slow the progression of movement problems in people with early-stage Parkinson's disease. Studies have found positive signs of fewer movement issues over two years, and these benefits appear to last even longer. Specifically, those who took prasinezumab experienced a slower decline in their ability to move and perform daily activities. This suggests that prasinezumab could help maintain movement and better control symptoms over time. The treatment targets a protein involved in Parkinson's, potentially protecting brain cells. Overall, the early results are promising for those with early-stage Parkinson’s. ^{1 3 4 5 6}

Who Is on the Research Team?

Clinical Trials

Principal Investigator

Hoffmann-La Roche

Are You a Good Fit for This Trial?

This trial is for individuals between 88-242 lbs with early-stage Parkinson's disease who meet specific diagnostic criteria and are on stable levodopa monotherapy. They must not have severe symptoms or be in advanced stages of the disease, and agree to follow contraception guidelines.

Inclusion Criteria

I agree to follow the study's birth control requirements.

I do not experience motor fluctuations due to Parkinson's disease.

My weight is between 88-242 lbs and my BMI is 18-34.

Timeline for a Trial Participant

Screening

Participants are screened for eligibility to participate in the trial

2-4 weeks

Treatment

Participants receive either Prasinezumab or placebo as an IV infusion during the double-blind treatment period

24 weeks

Follow-up

Participants are monitored for safety and effectiveness after treatment

4 weeks

Open-label extension

Eligible participants may enter into the Open Label Extension (OLE) phase to continue receiving Prasinezumab

Long-term

What Are the Treatments Tested in This Trial?

Interventions

• Prasinezumab

Trial Overview The study tests Prasinezumab against a placebo in participants with early Parkinson's. It aims to assess how effective and safe Prasinezumab is, as well as understand how the body processes it when taken alongside standard Parkinson's medication.

How Is the Trial Designed?

Group I: Prasinezumab Experimental Treatment 1 Intervention

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: Placebo Experimental Treatment 1 Intervention

Participants will receive placebo as an IV Infusion.

Who Is Running the Clinical Trial?

Hoffmann-La Roche

Lead Sponsor

Trials

2,482

Recruited

1,107,000+

Headquarters

Basel, Switzerland

Known For

Precision medicine

Top Products

Avastin, Herceptin, Rituxan, Accu-Chek

Dr. Levi Garraway

Hoffmann-La Roche

Chief Medical Officer since 2019

MD from the University of Basel

Dr. Thomas Schinecker

Hoffmann-La Roche

Chief Executive Officer since 2023

PhD in Molecular Biology from New York University

Prothena Biosciences Limited

Industry Sponsor

Trials

8

Recruited

1,200+

Citations

1. nature.com nature.com/articles/s41591-024-03270-6

Sustained effect of prasinezumab on Parkinson's disease ... Taken together, our results suggest that prasinezumab may slow motor progression and functional decline over the long term in early-stage PD. We ...

2. roche.com roche.com/media/releases/med-cor-2025-06-16

Roche to advance prasinezumab into Phase III ... Positive trends towards reduced motor progression at 104 weeks (two years) were observed; these effects appear to be sustained over longer ...

3. pubmed.ncbi.nlm.nih.gov pubmed.ncbi.nlm.nih.gov/39798255/

A Phase 2b, multicenter, randomized, double-blind ... Introduction: Prasinezumab was shown to potentially delay motor progression in individuals with early-stage Parkinson's disease (PD) who were ...

4. gene.com gene.com/media/press-releases/15067/2025-06-15/genentech-to-advance-prasinezumab-into-p

Genentech: Press Releases | Sunday, Jun 15, 2025 Positive trends towards reduced motor progression at 104 weeks (two years) were observed; these effects appear to be sustained over longer ...

5. sciencedirect.com sciencedirect.com/science/article/pii/S1353802024012690

A Phase 2b, multicenter, randomized, double-blind ... Prasinezumab was shown to potentially delay motor progression in individuals with early-stage Parkinson's disease (PD) who were either treatment-naïve or on ...

6. pmc.ncbi.nlm.nih.gov pmc.ncbi.nlm.nih.gov/articles/PMC8518716/

A Phase II Study to Evaluate the Safety and Efficacy of ... A Phase II study to evaluate the safety and efficacy of Prasinezumab in early Parkinson's disease (PASADENA): rationale, design, and baseline data.