Skip to content
Clinical Trials – home

Rare diseases

Investigational molecules

Locations

Our offerNewsroom

RecruitingRare disease

Study of ONC201 for Patients with Newly Diagnosed H3 K27M-mutant Diffuse Glioma After Radiotherapy

Fast replyInvestigationalNo placebo
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

What is this trial about?

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

This clinical trial is focused on studying a type of brain tumor called H3 K27M-mutant diffuse glioma. This is a specific kind of tumor that affects the brain and is known for having a particular genetic change, or mutation, called H3 K27M. The study is investigating a treatment using a medication known as ONC201, which is taken in the form of a capsule. The purpose of the study is to evaluate how effective ONC201 is when given to patients who have completed their initial treatment with radiation therapy.

Participants in the study will be randomly assigned to receive either the ONC201 medication or a placebo, which looks like the medication but does not contain the active ingredient. This is done to compare the effects of the actual medication against no treatment. The study is designed to be double-blind, meaning neither the participants nor the researchers will know who is receiving the actual medication or the placebo, to ensure unbiased results. The study will take place over a period of time, with regular check-ups and assessments to monitor the participants' health and the tumor's response to the treatment.

The main goals of the study are to see if ONC201 can help improve overall survival and delay the progression of the tumor. Researchers will also look at other factors, such as any side effects experienced by participants and changes in their quality of life. The study aims to provide valuable information on whether ONC201 can be a beneficial treatment option for people with H3 K27M-mutant diffuse glioma after they have completed radiation therapy.

The research process

The trial runs in 7 steps – from screening to follow-up. Each step says what happens and what the team monitors.

  1. Step 1

    Joining the study

    Upon joining the study, you will be asked to provide written informed consent. This means you agree to participate in the study after understanding the procedures involved. If you are unable to provide consent, a legally authorized representative may do so on your behalf.

  2. Step 2

    Initial assessments

    You will undergo an initial assessment to confirm your eligibility. This includes verifying your body weight, which must be at least 10 kg, and confirming a diagnosis of H3 K27M-mutant diffuse glioma through specific tests on tumor tissue.

    You will need to have a high-quality MRI scan of your brain taken before starting radiotherapy. If you had surgery, this scan should be done after the surgery. If not, it can be done before or after a biopsy.

  3. Step 3

    Post-radiotherapy assessment

    After completing standard radiotherapy, which should be done within 2 to 6 weeks before joining the study, another MRI scan of your brain will be required. This helps in assessing the effects of the radiotherapy.

  4. Step 4

    Randomization

    You will be randomly assigned to receive either the study medication ONC201 or a placebo. A placebo is a substance with no active medication, used to compare the effects of the actual drug.

  5. Step 5

    Medication administration

    If you are assigned to receive ONC201, you will take it in the form of a capsule. The specific dosage, frequency, and duration of administration will be provided by the study team.

  6. Step 6

    Ongoing assessments

    Throughout the study, you will have regular assessments to monitor your health and the effects of the treatment. This includes checking for any side effects and measuring your overall survival and progression-free survival, which refers to the time during and after treatment that you live without the disease getting worse.

  7. Step 7

    Completion of the study

    The study is expected to end by December 15, 2026. Upon completion, you will have a final assessment to evaluate the overall impact of the treatment.

Who can join the trial?

9 criteria

  • Able to understand the study procedures and agree to participate by providing written informed consent. This means you or your legal representative must sign a document agreeing to join the study.
  • Body weight must be at least 10 kg (about 22 pounds) at the time of joining the study.
  • Must have a new diagnosis of H3 K27M-mutant diffuse glioma. This is a specific type of brain tumor confirmed by testing the tumor tissue in a certified laboratory.
  • Must have at least one high-quality MRI scan of the brain with contrast before starting radiotherapy. If you had surgery to remove the tumor, this scan should be done after the surgery. If you only had a biopsy, the scan can be done before or after the biopsy.
  • Must have at least one high-quality MRI scan of the brain with contrast 2 to 6 weeks after finishing the initial radiotherapy. All available MRI scans done before starting the study treatment should also be provided.
  • Must have completed standard initial radiotherapy 2 to 6 weeks before joining the study. This radiotherapy should have been started within 12 weeks of the initial diagnosis and within 8 weeks of the most recent surgery or biopsy.
  • Must have a Karnofsky Performance Status or Lansky Performance Status of at least 70 at the time of joining the study. These are scales used to measure your ability to perform daily activities.
  • If you are taking corticosteroids (a type of medication) or anti-seizure medications, the dose must be stable or decreasing for 7 days before joining the study. A stable dose means no more than a 2 mg/day increase in the medication.
  • Participants can be male or female and must be within certain age ranges, which include children and adults.

Who cannot join the trial?

10 criteria

  • Patients who have not completed their radiotherapy treatment.
  • Patients with other types of brain tumors that are not H3 K27M-mutant diffuse glioma.
  • Patients who are not within the specified age range for the study.
  • Patients who are unable to follow the study procedures or instructions.
  • Patients who have other serious health conditions that might interfere with the study.
  • Patients who are pregnant or breastfeeding.
  • Patients who are participating in another clinical trial at the same time.
  • Patients who have had a recent surgery or medical procedure that might affect the study results.
  • Patients who have allergies or reactions to the study medication or similar drugs.
  • Patients who have a history of substance abuse or addiction.
Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.

We usually reply within a few days

Verified sites

All sites with verified contact details – recruitment status may not be available; ask directly

Trial locations

Where you can join this trial

Countries are shaded by recruitment status. Click a recruiting country to ask about joining there.

Recruiting
Not finding your country?

Not sure what to do next?

Joining a clinical trial can seem overwhelming. We guide you step by step, so you know exactly what to expect and how we support you through the process.

See the full process and FAQ

Investigated drugs

ONC201 is a medication being studied for its potential to treat a type of brain tumor called H3 K27M-mutant diffuse glioma. This medication is given to patients after they have completed their radiotherapy treatment. The goal of using ONC201 is to see if it can help improve the condition of patients with this specific type of brain tumor. It works by targeting certain pathways in the cancer cells, which may help to slow down or stop the growth of the tumor. This study is designed to understand how effective ONC201 is in treating this condition compared to not using the medication. Participants in the study will receive ONC201 to see if it can provide benefits in managing their brain tumor.

What is already known about the treatment

ONC201 – ONC201 is a medication administered orally, typically in the form of a pill, and is currently being studied in clinical trials for its potential use in treating a specific type of brain tumor known as H3 K27M-mutant diffuse glioma. This medication is not yet widely used in standard medical practice, as it is still under investigation to determine its effectiveness and safety. The main therapeutic indication for ONC201 is to help manage this aggressive brain tumor, particularly after patients have completed radiotherapy. At the molecular level, ONC201 works by targeting specific pathways in cancer cells that are involved in their growth and survival, aiming to slow down or stop the progression of the tumor. It is classified pharmacologically as an anti-cancer agent, specifically designed to interfere with the biological processes that allow cancer cells to thrive.

Investigated diseases

H3 K27M-mutant diffuse glioma – This is a type of brain tumor that occurs primarily in children and young adults. It is characterized by a specific genetic mutation known as H3 K27M, which affects the histone proteins in cells. The disease is classified as a high-grade glioma, meaning it is aggressive and tends to grow and spread quickly within the brain. As the tumor progresses, it can cause a variety of neurological symptoms, such as headaches, seizures, and changes in behavior or cognitive function. The tumor's growth can lead to increased pressure within the skull, further exacerbating symptoms. Over time, the disease can significantly impact the quality of life due to its effects on brain function.
Trial detailsLast updated 2 Oct 2026
Age18+ yearsPhasePhase IIITrial ID2022-502051-56-00Protocol codeONC201-108Estimated enrolment510 patientsSponsorChimerix Inc.

sourced from the EU Clinical Trials Register and site verification

Want to learn more about this trial or check if you can participate?

Clinical Trials Concierge

Prefer not to search? Our Concierge searches the trials for you.

Tell us about your condition – we search every trial in Europe and connect you with the right site.

ClinicalTrials.eu

Every clinical trial in Europe, in plain language.

Explore the full ecosystem of clinical research in Europe.

Search trials

Legal notice · Published by CTIN POLAND sp. z o.o., ul. rtm. Witolda Pileckiego 67/109, 02-781 Warsaw, Poland · KRS 0001111334 · REGON 528919042 · NIP 9512598637

© 2026 Clinical Trials EU – European Clinical Trials Information Network

GDPR compliance, ISO 9001 and ISO 27001 certified (LL-C Certification)

On this site, “treatment” means an investigational medicine being studied in a clinical trial. Its safety and efficacy for the use being studied have not yet been confirmed, some participants may receive a placebo or a comparator medicine, and taking part does not guarantee any health benefit. The decision to take part is made by the doctor at the research site. This site is for information only and does not replace medical advice.

This service is not affiliated with the European Commission, the EMA, or the official CTIS system. Most information comes from publicly available international clinical-trial registries, supplemented by data from academic sites, national regulators and commercial sponsors. On this site, “treatment” and “therapy” mean a medicine being tested in a clinical trial. Its safety and effectiveness in the use being studied are not yet confirmed, some participants may receive a placebo or a comparator, and taking part does not guarantee a health benefit. The doctor at the research site decides who can take part. This site provides information, not medical advice. Certain content and visual elements on this website have been generated or enhanced using artificial intelligence (AI).