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Study on Pain in Parkinson's Disease: Examining the Effects of 18F-MPPF in Patients with and without Pain

Verified siteInvestigationalNo placebo
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What is this trial about?

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

This clinical trial focuses on understanding pain in people with Parkinson's disease. The study will use a special imaging technique called positron emission tomography (PET) to explore the role of the serotonin system in pain. The treatment involves a solution for injection known as 18F-MPPF, which helps visualize certain brain activities during the PET scan.

The purpose of the study is to investigate how the brain processes pain in individuals with Parkinson's disease. Participants will be divided into two groups: those who experience pain and those who do not. The study will measure how 18F-MPPF is distributed in the brain, particularly in a region called the cerebellum, to understand differences between the two groups. Additionally, the study will look at how 18F-MPPF uptake relates to pain intensity and other pain characteristics, as well as how it connects to brain networks involved in pain perception.

Throughout the study, participants will undergo various assessments, including MRI scans, to examine brain structure and function. These assessments will help researchers understand the relationship between brain characteristics and pain experiences in Parkinson's disease. The study aims to provide insights into the mechanisms of pain in Parkinson's disease, potentially leading to better management strategies for those affected by this condition.

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 visit

    Upon joining the study, you will attend an initial visit where your eligibility will be confirmed. This includes verifying your diagnosis of Parkinson's disease and ensuring you meet the study criteria, such as age and stable treatment conditions.

    You will be asked to provide written consent to participate in the study. This consent confirms that you understand the study and agree to take part.

  2. Step 2

    Preparation for imaging

    Before the imaging procedure, you will receive an injection of a solution called 18F-MPPF. This is a special substance that helps to visualize certain brain activities during the scan.

    The injection is administered intravenously, meaning it is given through a vein. The procedure is similar to having a blood test.

  3. Step 3

    Positron emission tomography (PET) scan

    You will undergo a positron emission tomography (PET) scan. This imaging test allows researchers to explore the serotonin system in your brain, which is related to pain processing in Parkinson's disease.

    During the scan, you will be asked to lie still on a table that slides into a large, circular machine. The scan is painless and typically lasts about an hour.

  4. Step 4

    Resting-state functional MRI

    In addition to the PET scan, a resting-state functional MRI will be conducted. This test examines the functional networks in your brain while you are at rest.

    The MRI scan is similar to the PET scan in terms of procedure and duration. It helps to compare brain activity related to pain between different groups of patients.

  5. Step 5

    Follow-up and feedback

    After the imaging procedures, you may be asked to attend follow-up visits. These visits are to monitor your condition and gather additional information if needed.

    You will receive feedback on the findings related to your participation in the study. This information can provide insights into the pain mechanisms associated with Parkinson's disease.

Who can join the trial?

7 criteria

  • Patients with Parkinson's disease as defined by specific medical criteria.
  • Men and women aged between 40 and 80 years.
  • Patients who have been on a stable treatment for Parkinson's disease for at least 4 weeks before joining the study.
  • Patients with a MOCA score greater than 25. (MOCA is a test that checks memory and thinking skills.)
  • Patients with a HADS-D score of 11 or less. (HADS-D is a questionnaire that measures levels of depression.)
  • Person must be affiliated with or benefiting from a social security scheme.
  • Participants must provide free, informed, and written consent signed by both the participant and the investigator before any study-related procedures.

Who cannot join the trial?

3 criteria

  • Patients who do not have Parkinson's disease cannot participate.
  • Patients who are not within the specified age range cannot participate.
  • Patients who belong to a vulnerable population cannot participate.
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Investigated drugs

[18F]-MPPF is a special type of imaging agent used in a PET scan. In this clinical trial, it helps doctors see how the serotonin system is working in the brain of people with Parkinson's disease. The goal is to understand the role of serotonin in pain experienced by these patients. This imaging agent is not a treatment but a tool to help researchers learn more about the disease.

What is already known about the treatment

[18F]-MPPF – This medication is administered through an injection and is used in a specialized imaging technique called positron emission tomography (PET) to study the brain. Currently, it is being researched in clinical trials to understand its role in exploring the serotonin system in patients with Parkinson's disease, particularly focusing on pain. The main therapeutic indication is to help visualize and measure serotonin receptor activity in the brain, which can provide insights into the pathophysiology of pain in Parkinson's disease. At the molecular level, [18F]-MPPF binds to serotonin receptors, allowing researchers to see how these receptors are distributed and functioning in the brain. It is classified as a radiopharmaceutical used for diagnostic imaging.

Investigated diseases

Parkinson's disease – Parkinson's disease is a progressive neurological disorder that affects movement. It is characterized by tremors, stiffness, and difficulty with balance and coordination. The disease progresses gradually, often starting with a barely noticeable tremor in one hand. As it advances, individuals may experience slower movement, muscle rigidity, and impaired posture. Non-motor symptoms such as sleep disturbances, mood changes, and cognitive impairment can also occur. Over time, these symptoms can become more pronounced, affecting daily activities and quality of life.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2022-501123-24-00Protocol codeRC31/21-0566Estimated enrolment34 patientsSponsorCentre Hospitalier Universitaire De Toulouse

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