Active not recruitingPHASE2INTERVENTIONAL

A Study to Evaluate the Efficacy and Safety of Intravenous Prasinezumab in Participants With Early Parkinson's Disease

This study is investigating a new medication called prasinezumab for individuals who have recently been diagnosed with Parkinson's disease. The main goals are to find out if this new treatment is safe and if it can help improve symptoms. Participants will be randomly given either prasinezumab, given through a drip into a vein, or a placebo (an inactive dummy treatment). This is a 'double-blind' study, meaning neither the patient nor the researchers will know who is receiving which treatment until the study ends. Everyone in the study will already be taking approved Parkinson's medications at stable doses. The study involves many hospitals and clinics, and researchers hope to see if prasinezumab can make a difference in managing early Parkinson's.

At a glance

Status

Active not recruiting

Phase

PHASE2

Sponsor

Hoffmann-La Roche

Enrolment target

586

Start

05 May 2021

Estimated completion

30 Dec 2026

Parkinsons Disease

Results

Results from this study

Posted December 2025

Results have been published for this study.

Primary outcome

DBT Period: Time to Confirmed Motor Progression Event Assessed by Movement Disorder Society - Unified Parkinson's Disease Rating Scale (MDS-UPDRS) Part III

Time to confirmed motor progression event was the first time point of a worsening event defined as either \>= 5 points increase in MDS-UPDRS Part III score (assessed in "OFF" medication state) from baseline sustained over 2 consecutive assessments or a change in medication after first occurrence of \>= 5 points increase in MDS-UPDRS Part III score from baseline \& before follow-up assessment. MDS-UPDRS Part III is a clinician rater scale that assessed the motor signs of PD. The scale is composed of 18 clinical domains or tasks, which yield 33 distinct scores or ratings. For each distinct rating, a numeric score is assigned between 0-4, where 0 = Normal, 1 = Slight, 2 = Mild, 3 = Moderate, and 4 = Severe. The total MDS-UPDRS Part III score (ranging from 0 to 132) is calculated by summing these 33 individual ratings, with higher scores indicating severe impairment.

Full results on the registry

What is this study about?

This study is focused on people who have been diagnosed with Parkinson's disease fairly recently, specifically within the last three months to three years. The main idea behind the research is to test a new medicine, called prasinezumab, which is given directly into a vein (intravenously). For people with Parkinson's, certain brain cells that produce a chemical called dopamine stop working properly. Researchers believe prasinezumab might help by targeting specific processes in the body linked to how Parkinson's progresses.

The study aims to understand two key things. Firstly, they want to see how effective prasinezumab is at improving or stabilising the symptoms of Parkinson's disease compared to a placebo. Secondly, and just as important, they want to carefully check if the medication is safe and what side effects it might have. Since this is an early-stage trial (Phase 2), the dose and how often the medicine is given will be carefully monitored.

Taking part in a study like this is important because it helps scientists learn more about new treatments that could potentially help people with Parkinson's disease in the future. All participants will continue to receive their standard Parkinson's medications throughout the study, which allows researchers to see if prasinezumab adds any extra benefit.

Key takeaways

Tests a new medicine (prasinezumab) for early Parkinson's disease.
Compares the new medicine to a dummy treatment (placebo).
Focuses on safety and whether it improves symptoms.
Participants continue their regular Parkinson's medications.
Involves regular clinic visits and using a smartphone/smartwatch.
Helps advance research for future Parkinson's treatments.

Who may be eligible?

To be considered for this study, you would typically need to have received a diagnosis of Parkinson's disease between three months and three years ago. Your doctor would need to confirm your diagnosis based on specific criteria, and you should already be taking regular Parkinson's medications at a steady dose for at least three months.

There are also some medical checks involved. For example, brain scans would be done to confirm your type of Parkinson's and to make sure there are no other major brain health issues. You would also need to be generally in good health, without other serious medical conditions like uncontrolled high blood pressure or significant heart problems in the past year. Your blood test results would also need to be within a healthy range.

People who have other types of Parkinson's-like conditions, those with Parkinson's disease affecting their memory (dementia), or individuals with a history of alcohol or drug abuse in the last year, would not be able to join. An allergy to any part of the study drug or issues with having an MRI scan would also prevent participation.

Could this study suit you?

Answer these quick questions to see if you may be eligible. This is a guide only — the research team makes the final call.

Have you been diagnosed with Parkinson's disease between 3 months and 3 years ago?
Are you currently taking stable doses of Parkinson's medications?
Do you have a general good health, without other serious medical conditions?
Are you able to have MRI scans and other required medical tests?
Would you be willing to use a smartphone app and wear a smartwatch for the study?

Answer every question to see your result.

What does participation involve?

Taking part in this study would involve regular visits to a clinic or hospital over several months. You would receive the study medication (either prasinezumab or a placebo) through a drip into your vein during these visits. There will be various assessments throughout the study, including medical check-ups, physical examinations, and blood tests. You might also have repeat brain scans to monitor your condition and to ensure your safety.

A key part of the study involves using a smartphone app and wearing a smartwatch. These devices will help researchers track your Parkinson's symptoms and movement patterns in your daily life. You'll need to be willing to use these throughout the study. The total duration of your participation in the study, including follow-up appointments, will be clearly explained by the study team.

Potential risks and benefits

While there's no guarantee of direct personal benefit, you might contribute to important research that could help others with Parkinson's disease in the future. As with any medication, prasinezumab could have side effects, and some people might experience discomfort or allergic reactions. The research team will carefully monitor you for any potential risks or side effects. Always remember, joining a clinical study is completely voluntary, and you have the right to withdraw at any time without explaining why, and this will not affect your usual medical care.

Locations (110)

Some site locations are approximate. We're improving this — please verify with the trial team before travelling.

University of Alabama at Birmingham
Verified postcode
Birmingham, United States
Barrow Neurological Institute
Verified postcode
Phoenix, United States
Neurology Center of North Orange County
Verified postcode
Fullerton, United States
UC San Diego
Verified postcode
La Jolla, United States
Keck School of Medicine of USC
Verified postcode
Los Angeles, United States
Cedars Sinai Medical Center
Verified postcode
Los Angeles, United States
University of California San Francisco
Verified postcode
San Francisco, United States
CenExel Rocky Mountain Clinical Research, LLC
Verified postcode
Englewood, United States
Institute for Neurodegenerative Disorders
Verified postcode
New Haven, United States
JEM Research LLC
Verified postcode
Atlantis, United States
Parkinson's Disease and Movement Disorders Center of Boca Raton
Verified postcode
Boca Raton, United States
Renstar Medical Research
Verified postcode
Ocala, United States

Common questions

What is Parkinson's Disease?

Parkinson's disease is a condition where certain brain cells stop working, leading to problems with movement like tremors, stiffness, and slow movement.

What is a 'placebo'?

A placebo is a dummy treatment that looks just like the real medicine but contains no active drug. It helps researchers see the true effect of the new medicine.

What does 'double-blind' mean?

Double-blind means that neither you nor your study doctor will know whether you are receiving the active drug or the placebo. This helps make the study results fair and unbiased.

Will I stop my current Parkinson's medication?

No, you will continue to take your usual Parkinson's medications at a stable dose throughout the study. The study medication is given in addition to your current treatment.

How is prasinezumab given?

Prasinezumab is given intravenously, which means it's delivered directly into a vein through a drip.