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Study on the Effects and Safety of Prasinezumab for Patients with Early Parkinson's Disease

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What is this trial about?

A plain-language summary of the goals, design and what participants do

This clinical trial is focused on studying the effects of a treatment for Parkinson's disease, specifically in its early stages. Parkinson's disease is a condition that affects movement, causing symptoms like tremors, stiffness, and difficulty with balance and coordination. The treatment being tested is called prasinezumab, which is given as a solution through an intravenous (IV) infusion. This means the medication is delivered directly into the bloodstream through a vein. Prasinezumab is also known by other names, such as RO7046015 and RG7935.

The purpose of this study is to evaluate how effective prasinezumab is compared to a placebo in delaying the progression of motor symptoms in people with early Parkinson's disease. Participants in the study will receive either prasinezumab or a placebo through IV infusions. The study will monitor the time it takes for participants to experience a confirmed worsening of their motor symptoms. This will help researchers understand if prasinezumab can slow down the progression of the disease.

Throughout the study, participants will be regularly assessed to track any changes in their motor function and overall health. This includes monitoring for any side effects or adverse reactions to the treatment. The study aims to provide valuable information on the safety and effectiveness of prasinezumab for individuals with early Parkinson's disease, potentially leading to better treatment options in the future.

The research process

The trial runs in 5 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Initial assessment

    Upon joining the study, an initial assessment is conducted to confirm eligibility. This includes a diagnosis of early Parkinson's disease, stable medication doses, and specific scores on Parkinson's disease rating scales.

  2. Step 2

    Randomization

    Participants are randomly assigned to receive either the study medication, prasinezumab, or a placebo. This process is double-blind, meaning neither the participant nor the study team knows which treatment is being administered.

  3. Step 3

    Treatment administration

    The treatment involves an intravenous infusion of the solution. The frequency and dosage are determined by the study protocol and are administered at regular intervals throughout the study duration.

  4. Step 4

    Monitoring and assessments

    Regular monitoring is conducted to assess motor function and overall health. This includes evaluations using the Movement Disorder Society - Unified Parkinson's Disease Rating Scale (MDS-UPDRS) and other health assessments.

    Participants are monitored for any adverse events or changes in health status, including vital signs, electrocardiogram (ECG) assessments, and laboratory measurements.

  5. Step 5

    End of study evaluation

    At the conclusion of the study, a final evaluation is conducted to assess the efficacy and safety of the treatment. This includes a review of motor function progression and any adverse events experienced during the study.

Who can join the trial?

8 criteria

  • Have a diagnosis of **idiopathic Parkinson's disease (PD)**. This means Parkinson's disease with no known cause, based on specific criteria that include **bradykinesia** (slowness of movement) and at least one other main symptom like **resting tremor** (shaking when not moving) or **rigidity** (stiffness).
  • Be taking medication for Parkinson's disease that helps with symptoms, and have been on stable doses for at least 3 months before starting the study.
  • Have been diagnosed with Parkinson's disease for at least 3 months but not more than 3 years at the time of screening for the study.
  • Have a score of 0 on a specific part of a Parkinson's disease rating scale (MDS-UPDRS Part IV) at screening and before being randomly assigned to a treatment group. This part of the scale measures complications from treatment.
  • Be at **Hoehn and Yahr (H&Y) Stage I or II** when not on medication at screening and before randomization. This scale measures the severity of Parkinson's disease, with Stage I being mild and Stage II being slightly more advanced.
  • Have results from a specific type of brain imaging test (**DaT-SPECT**) that show a deficit in the **dopamine transporter**, which is a sign of Parkinson's disease, as confirmed by a central reader.
  • Be within the age range of 18 to 80 years old.
  • Both male and female participants are eligible.

Who cannot join the trial?

5 criteria

  • Patients who have a different condition than early Parkinson's disease cannot participate.
  • Patients who are not within the specified age range cannot participate. The age range is typically defined by the study, but it is not specified here.
  • Patients who do not fit into the specific clinical trial group cannot participate. The group is usually defined by the study, but it is not specified here.
  • Both male and female patients are considered, so gender is not an exclusion factor.
  • Patients who are part of a vulnerable population may be excluded. This term refers to groups who might be at a higher risk of harm or exploitation, such as children, pregnant women, or those with certain disabilities.
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Investigated drugs

Prasinezumab is an investigational medication being studied for its potential to treat early Parkinson's disease. It is administered intravenously, meaning it is given directly into a vein. The goal of this medication in the trial is to see if it can slow down the progression of motor symptoms in people with early Parkinson's disease.

What is already known about the treatment

Prasinezumab – Prasinezumab is administered intravenously, meaning it is given directly into a vein through an injection. It is currently being studied in clinical trials for its potential use in treating early Parkinson's disease. The main therapeutic indication for prasinezumab is to slow the progression of motor symptoms in individuals with early-stage Parkinson's disease. At the molecular level, prasinezumab is believed to work by targeting and binding to a protein called alpha-synuclein, which is involved in the development of Parkinson's disease. This medication falls under the pharmacological classification of monoclonal antibodies, which are designed to target specific proteins in the body.

Investigated diseases

Early Parkinson's Disease – This is a neurodegenerative disorder that primarily affects movement. It begins with mild symptoms such as tremors, stiffness, and slowness of movement. As the disease progresses, these symptoms become more pronounced and can interfere with daily activities. People with early Parkinson's disease may also experience changes in posture, balance, and coordination. Non-motor symptoms, such as sleep disturbances and mood changes, can also occur. The progression of symptoms varies from person to person, and the rate of progression can differ significantly.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IVTrial ID2023-507132-21-00Protocol codeBN42358Estimated enrolment586 patientsSponsorF. Hoffmann-La Roche AG

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