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[18F]CPFPX PET in Patients With Drug-Resistant Epilepsy and Healthy Subjects

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 study is looking at epilepsy, especially drug-resistant epilepsy, which means seizures that are not well controlled by usual medicine. The study also includes healthy subjects for comparison. The purpose of the study is to see how epilepsy may affect brain areas that help control breathing and wakefulness. The main test treatment is [18F]CPFPX, a substance given by injection and used in PET, a special brain scan that shows how the brain is working.

In the study, [18F]CPFPX is used to look at certain brain receptors called A1 receptors, which are proteins that help cells respond to signals. The study follows people during a breathing challenge and then compares brain scan results between people with drug-resistant epilepsy and healthy subjects. It also looks at brainstem size on MRI, which is a scan that uses magnetic fields to take detailed pictures of the brain, and relates these findings to breathing response and daily caffeine intake.

The study is expected to continue over several years. A short scan and breathing testing are done during the study, and the results are compared between the groups. No treatment for epilepsy is being tested here; this is a research study using [18F]CPFPX to learn more about brain changes in epilepsy.

The research process

The trial runs in 4 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Study participation begins

    After joining the study, you receive a single injection of [18f]cpfpx, which is the test substance used in the trial.

    The dose is 275 mbq (megabecquerels, a unit used to measure the amount of radioactive material).

    The injection is given once and the study record does not list any repeated doses.

  2. Step 2

    Imaging and breathing-related measurements

    After the injection, you take part in pet imaging. pet means positron emission tomography, a scan that shows how the test substance is distributed in the body.

    The trial compares the distribution of the test substance in the brainstem and in other brain areas while breathing under hypercapnic conditions. hypercapnic means that there is more carbon dioxide in the air you breathe than usual.

    You also have measurements related to breathing control, including the hcvr slope. hcvr means hypercapnic ventilatory response, which is a measure of how your breathing changes when carbon dioxide levels rise.

    The study also evaluates the pattern of brain activity during bh. bh means breath-holding.

  3. Step 3

    Mri scan

    You have an mri scan. mri means magnetic resonance imaging, a scan that creates detailed pictures of the brain.

    The scan is used to compare the size of brainstem areas between patients with drug-resistant epilepsy and healthy subjects.

  4. Step 4

    Study comparisons and follow-up of recorded data

    The study compares the results from your scans and breathing measurements with those of healthy subjects.

    The study also looks at the relationship between your measured brain findings and your daily caffeine intake, reported as milligrams per day.

Who can join the trial?

8 criteria

  • Written informed consent must be given. This means the person must sign the study consent form after being told about the study.
  • The person must be able to follow the study requirements, meaning they can attend visits and do what the study asks.
  • The person must be between 18 and 55 years old.
  • The patient must have focal epilepsy or idiopathic generalized epilepsy. Focal epilepsy means seizures start in one part of the brain. Idiopathic generalized epilepsy means seizures start in both sides of the brain and the cause is not known.
  • The patient must have refractory epilepsy, also called drug-resistant epilepsy. This means at least two suitable anti-seizure medicine treatments have been tried and did not control the seizures well enough.
  • The patient must have had at least 3 tonic-clonic seizures in the past 18 months. A tonic-clonic seizure is a seizure with body stiffening and shaking. It may be focal to bilateral tonic-clonic, meaning it starts in one part of the brain and then affects both sides, or generalized tonic-clonic, meaning it affects both sides from the start.
  • For women who can become pregnant, highly effective contraception must be used until the end of the relevant study exposure period. Contraception means a method used to prevent pregnancy.
  • For healthy subjects, the same requirements apply: written informed consent, ability to follow the study requirements, age 18 to 55 years, and for women who can become pregnant, use of highly effective contraception until the end of the relevant study exposure period.

Who cannot join the trial?

17 criteria

  • Ongoing or chronic breathing failure, meaning shortness of breath of grade 2 or higher on a standard scale, or being treated by a lung specialist for breathing problems.
  • Obstructive sleep apnea, which means a diagnosed condition where breathing stops and starts during sleep, even if treatment is already being used.
  • MRI not allowed, such as having metal in the body or severe fear of closed spaces.
  • History of stroke in the last 5 years.
  • Brain lesion with swelling or pressure effect on MRI or CT scan, meaning an abnormal area in the brain that takes up space and may cause swelling or pressure.
  • Vagus nerve stimulation or deep brain stimulation, which are treatments using implanted electrical devices.
  • Heart failure with symptoms of grade 2 or higher, or being treated by a heart specialist for long-term heart failure.
  • Ischemic heart disease, meaning reduced blood flow to the heart, including a history of heart ischemia or typical angina. Angina is chest pain caused by poor blood flow to the heart.
  • Current treatment with certain antidepressants, including SSRIs and SNRIs. SSRIs and SNRIs are medicines used for depression and anxiety. The medicines are: citalopram, escitalopram, fluoxetine, fluvoxamine, paroxetine, sertraline, duloxetine, milnacipran, and venlafaxine.
  • Allergy or hypersensitivity to [18F]-CPFPX, meaning a known bad reaction to the study tracer.
  • Pregnancy, labor, or breastfeeding.
  • Positive urine pregnancy test at the study visit, if the test is needed.
  • Psychiatric disorder under compulsory care, meaning a mental health condition treated because of a legal order.
  • Deprived of liberty because of a judicial or administrative decision, such as being in prison or detention.
  • Under legal protection, such as guardianship or curatorship, which means another person legally helps make decisions.
  • Not covered by social security or a similar health coverage scheme.
  • For healthy volunteers only: History of epilepsy.
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Investigated drugs

[18F]CPFPX – This is a test imaging tracer used in a PET scan. It is given by injection and helps doctors see where a certain brain receptor called the adenosine A1 receptor is located. In this trial, it is used to compare brainstem activity in people with drug-resistant epilepsy and in healthy volunteers, especially in areas involved in breathing control when carbon dioxide levels are high.

What is already known about the treatment

[18F]CPFPX - [18F]CPFPX is a radioactive medicine used as a solution for injection and is given into a vein before a PET scan, most often in specialist research or hospital settings. It is used in medical studies to help picture where adenosine A1 receptors are found in the brain, especially in areas that help control breathing and alertness, and it is not a routine treatment medicine. This substance belongs to the group of PET imaging agents and adenosine receptor tracers, and it works by binding to A1 receptors so the scanner can detect their distribution; in medicine and the scientific literature, it is mainly known as a research tool rather than a standard therapy.

Investigated diseases

Drug-resistant epilepsy - A form of epilepsy in which seizures continue despite the use of appropriate anti-seizure medicines. It develops as repeated seizure episodes that do not respond well to standard treatment, and the seizures may remain frequent or vary over time. The disorder can affect different parts of the brain and may be associated with changes in brain activity and structure.
Trial detailsLast updated 7 Oct 2026
Age18+ yearsPhasePhase IITrial ID2025-524511-36-00Protocol code69HCL25_0757Estimated enrolment50 patientsSponsorHospices Civils De Lyon

sourced from the EU Clinical Trials Register and site verification

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