NCT05580562 · Chimerix
ONC201 in H3 K27M-mutant Diffuse Glioma Following Radiotherapy (the ACTION Study)
(ACTION)
What this study is about
This is a randomly assigned, where neither patients nor doctors know which treatment is given, compared against an inactive treatment, parallel-group, international, Phase 3 study in patients with newly diagnosed H3 K27M-mutant diffuse glioma to assess whether treatment with ONC201 following frontline radiotherapy will extend how long patients live and time without the disease getting worse in this population. Eligible participants will have histologically diagnosed H3 K27M-mutant diffuse glioma and have completed standard frontline radiotherapy.
View original scientific description
This is a randomized, double-blind, placebo-controlled, parallel-group, international, Phase 3 study in patients with newly diagnosed H3 K27M-mutant diffuse glioma to assess whether treatment with ONC201 following frontline radiotherapy will extend overall survival and progression-free survival in this population. Eligible participants will have histologically diagnosed H3 K27M-mutant diffuse glioma and have completed standard frontline radiotherapy.
Interventions
DRUG
Dordaviprone (ONC201)
Participants ≥ 52.5 kg will receive 625 mg of dordaviprone (5 × 125-mg capsules) dosing days; participants \< 52.5 kg will receive a dose (and corresponding number of capsules) scaled by body weight and rounded to 125-mg increments.
DRUG
Dordaviprone (ONC201) + Placebo
Participants ≥ 52.5 kg will receive 625 mg of dordaviprone (5 × 125-mg capsules) or matching placebo on dosing days; participants \< 52.5 kg will receive a dose (and corresponding number of capsules) scaled by body weight and rounded to 125-mg increments
OTHER
Placebo
Participants will receive placebo (same number of capsules as the dordaviprone dose) on dosing days
Primary outcome measures
Overall survival (OS)
Time frame: From date of randomization until date of death from any cause, assessed up to approximately 44 months
Overall Survival is defined as the time from randomization to death due to any cause.
Who can participate
This study lists these criteria on ClinicalTrials.gov. A study coordinator reviews eligibility during screening — this page does not determine whether you qualify.
Inclusion criteria
- Able to understand the study procedures and agree to participate in the study by providing written informed consent (by participant or legally authorized representative), and assent when applicable. 2. Body weight ≥ 10 kg at time of randomization. 3. Histologically diagnosed H3 K27M-mutant diffuse glioma (new diagnosis). Detection of a missense K27M mutation in any histone H3-encoding gene detected by testing of tumor tissue (immunohistochemistry \[IHC\] or next-generation sequencing \[NGS\] in a Clinical Laboratory Improvement Amendments \[CLIA\]-certified or equivalent laboratory). \[Site to provide (as available): ≥ 10 unstained formalin-fixed paraffin-embedded (FFPE) slides from tumor tissue.\] 4. At least one, high-quality, contrast-enhanced MRI of the brain obtained prior to starting radiotherapy for submission to sponsor's imaging vendor for central read. For participants who had a surgical resection, this scan must be post-resection; for participants who
Where
- Phoenix, Arizona
- La Jolla, California
- Los Angeles, California
- Orange, California
- San Francisco, California
- Santa Monica, California
- Stanford, California
- New Haven, Connecticut
- Washington D.C., District of Columbia
- Jacksonville, Florida
- Miami, Florida
- Tampa, Florida
And 39 more locations — see the full list below.
Collaborators
Chimerix, Inc.
Related conditions & keywords
Frequently asked questions
What is a clinical trial?
A clinical trial is a research study that tests new medical treatments, drugs, devices, or procedures to determine their safety and effectiveness. Trials are carefully designed and monitored to protect participants while advancing medical knowledge.
Is it safe to participate?
Clinical trials follow strict safety guidelines and ethical standards. Trials must be reviewed and approved, and participants are closely monitored by medical professionals throughout the study. You can withdraw at any time if you choose.
Will I be compensated?
Many clinical trials offer compensation for your time, travel expenses, and inconvenience. The specific compensation varies by study and will be discussed during the screening process. All study-related medical care is typically provided at no cost to participants.
Will I receive a placebo instead of treatment?
When effective treatment exists, participants typically receive either the standard treatment plus the study intervention, or the standard treatment plus placebo. You would not be denied effective care. Placebos are primarily used when no proven treatment is available, or in addition to standard care. Your trial consent form will clearly explain what treatments you may receive.
Can I leave a trial if I change my mind?
Absolutely. Participation in clinical trials is completely voluntary. You have the right to withdraw from the study at any time, for any reason, without penalty or loss of benefits to which you are otherwise entitled.
How long does a clinical trial last?
Trial duration varies widely depending on the study design and purpose. Some trials last just a few weeks, while others may continue for months or years. The study coordinator will provide specific timeline information during your screening call.
Data: ClinicalTrials.gov · synced Apr 16, 2026 · Source of record for eligibility and locations