ONC206 for Treatment of Newly Diagnosed, or Recurrent Diffuse Midline Gliomas, and Other Recurrent Malignant CNS Tumors (PNOC 023)

Open to people ages 2-21

• ARM A: Children and young adults with DMG (2-21 years of age) who completed at least one line of prior therapy. Prior treatment must have included focal radiation therapy and patients must be within 4-14 weeks from completion of radiation therapy and have no evidence of disease progression
• ARM A: Tumor tissue confirmation of DMG is mandatory and pathology must be consistent with a DMG including DMG H3K27M mutant and World Health Organization (WHO) grade III and IV H3 wildtype gliomas. WHO grade II diffuse astrocytomas or other low grade gliomas without H3K27M mutation are not eligible
• ARM A: Participants must have recovered from all acute side effects of prior therapy. From the projected start of scheduled study treatment, the following time periods must have elapsed: 5 half-lives from any investigational agent, 4 weeks from cytotoxic therapy (except 23 days for temozolomide and 6 weeks from nitrosoureas), 4 weeks from antibodies and must be at least 7 days since the completion of therapy with a biologic or small molecule agent. For any biologic or small molecule agent with known adverse events that can occur beyond 7 days after administration, the period prior to enrollment must be beyond the time during which adverse events are known to occur (these should be discussed with the study team)
• ARM B: Newly diagnosed children and young adults (2-21 years of age) with a diagnosis of DMG are eligible, including spinal cord DMGs
• ARM B: Tumor tissue confirmation of DMG is mandatory and pathology must be consistent with a DMG including DMG H3K27M mutant and WHO grade III and IV H3 wildtype gliomas. WHO grade II diffuse astrocytomas or other low grade gliomas without H3K27M mutation are not eligible
• ARM C: Children and young adults with DMGs (2-21 years of age) who have evidence of first progression but have not been treated for this progression and are recommended to get reirradiation
• ARM C: Patients must have undergone prior focal radiation therapy as part of their initial therapy and should be at least 6 months from prior radiation therapy. If timing is less than 6 months from prior focal radiation, these patients need to be discussed with the study chair(s)
• ARM C: Tumor tissue confirmation of DMG is mandatory and pathology must be consistent with a DMG including DMG H3K27M mutant and WHO grade III and IV H3 wildtype gliomas. WHO grade II diffuse astrocytomas or other low grade gliomas without H3K27M mutation are not eligible
• ARM C: Participants must have recovered from all acute side effects of prior therapy
• ARM C: From the projected start of scheduled study treatment, the following time periods must have elapsed: 5 half-lives from any investigational agent, 4 weeks from cytotoxic therapy (except 23 days for temozolomide and 6 weeks from nitrosoureas), 4 weeks from antibodies and must be at least 7 days since the completion of therapy with a biologic or small molecule agent. For any biologic or small molecule agent with known adverse events that can occur beyond 7 days after administration, the period prior to enrollment must be beyond the time during which adverse events are known to occur (these should be discussed with the study team)
• ARM D: Children and young adults with recurrent primary malignant CNS tumors (2 - 21 years of age) who have evidence of progression but have not been treated for this progression
• ARM D: Tumor tissue confirmation is mandatory and pathology must be consistent with recurrent primary malignant CNS tumor (diagnosis of recurrent ependymoma is allowed)
• ARM D: Participants must have recovered from all acute side effects of prior therapy
• ARM D: From the projected start of scheduled study treatment, the following time periods must have elapsed: 5 half-lives from any investigational agent, 4 weeks from cytotoxic therapy (except 23 days for temozolomide and 6 weeks from nitrosoureas), 4 weeks from antibodies and must be at least 7 days since the completion of therapy with a biologic or small molecule agent. For any biologic or small molecule agent with known adverse events that can occur beyond 7 days after administration, the period prior to enrollment must be beyond the time during which adverse events are known to occur (these should be discussed with the study team)
• ARM D: Participants who are receiving dexamethasone must be on a stable or decreasing dose for at least 3 days prior to baseline magnetic resonance imaging (MRI) scan
• TARGET VALIDATION: Newly diagnosed children and adults (2 years of age and above) with imaging consistent with a DMG are eligible
• TARGET VALIDATION: Children and young adults with recurrent primary malignant CNS tumors, including recurrent DMG, (2 years of age and above) who have evidence of progression but have not been treated for this progression
• TARGET VALIDATION: Participants must undergo tumor tissue collection as part of their standard of care
• Participants who are receiving steroids must be on a stable or decreasing dose for at least 3 days prior to baseline MRI scan
• Peripheral absolute neutrophil count (ANC) >= neutrophil 1.0 g/l
• Platelet count >= 100 x 10⁹/L (transfusion independent, defined as not receiving platelet transfusions for at least 7 days prior to enrollment)
• Creatinine clearance or radioisotope glomerular filtration rate (GFR) >= 90 mL/min/1.73 m² or a serum creatinine based on age/gender equal upper limit of normal
• Bilirubin (sum of conjugated + unconjugated) =< 1.5 x upper limit of normal (ULN) for age
• Serum glutamic pyruvic transaminase (SGPT) (alanine aminotransferase (ALT)) =< 2 x ULN
• Patients with seizure disorder may be enrolled if seizure disorder is well controlled

• The effects of ONC206 on the developing human fetus is unknown. For this reason, females of child-bearing potential and males must agree to use adequate contraception.

  Adequate methods include: hormonal or barrier method of birth control; or abstinence prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while she or her partner is participating in this study, she should inform her treating physician immediately. Males treated or enrolled on this protocol must also agree to use adequate contraception prior to the study and for the duration of study participation

• Karnofsky >= 50 for participants > 16 years of age and Lansky >= 50 for participants =< 16 years of age. Participants who are unable to walk because of paralysis, but who are up in a wheelchair, will be considered ambulatory for the purpose of assessing the performance score
• Subjects must be willing to provide archival formalin-fixed embedded (FFPE) and frozen tissue specimens for biomarker studies, if available
• A legal parent/guardian or participant must be able to understand, and willing to sign, a written informed consent and assent document, as appropriate

• Participants who are currently receiving another investigational drug are not eligible
• Participants who are currently receiving other anti-cancer agents are not eligible
• Participants with a known disorder that affects their immune system, such as human immunodeficiency virus (HIV) or hepatitis B or C, or an auto-immune disorder requiring systemic cytotoxic or immunosuppressive therapy are not eligible. Note: Participants that are currently using inhaled, intranasal, ocular, topical or other non-oral or non-intravenous (IV) steroids are not necessarily excluded from the study but need to be discussed with the study chair
• Participants with uncontrolled infection
• Female participants of childbearing potential must not be pregnant or breast-feeding. Female participants of childbearing potential must have a negative serum or urine pregnancy test prior to the start of therapy
• Active illicit drug use or diagnosis of alcoholism
• History of allergic reactions attributed to compounds of similar chemical or biologic composition to ONC206
• Inability to follow the procedures of the study, e.g. due to language problems, psychological disorders, dementia, etc. of the participant or family
• Any participants with illnesses that may affect absorption of ONC206
• Any participants on strong inhibitors or inducers of CYP3A4, 2D6, 1A2, 2C9 and 2C19 at least 14 days prior and throughout the study