Phase I Study of Oral ONC206 in Recurrent and Rare Primary Central Nervous System Neoplasms

This is a Phase I, open-label, dose-escalation, and exploratory study of ONC206 in patients with recurrent, primary CNS neoplasms. All patients will be informed about the study and potential risks and required to provide written informed consent prior to undergoing study-related procedures. There will be a total of 11 Dose Levels. Dose-escalation for Dose Levels 1 through 5 proceeded according to standard 3+3 design using a 28-day DLT window. The first cohort of 3 patients enrolled into the study received Dose Level 1 followed by increments as per the modified Fibonacci sequence. It is anticipated that approximately 46 patients will be enrolled in order to determine the MTD of ONC206. For Dose Levels 1 through 5, a safety evaluation was conducted when 3 evaluable patients have completed 1 cycle (28 days) of therapy. After Protocol Amendment 6, all available PK data will also be considered for dose escalation decisions. Dose levels may be adjusted based on review of PK data but will not exceed maximum dose levels described in Table 6. Additionally, dose frequencies (e.g., once daily or 3 times daily) may be added and/or removed based on emerging PK data and concentration projections. Prior to advancing/changing dose levels, a cohort summary must be completed and submitted to the sponsor Medical Monitor, for review and approval. Dose escalation for subsequent patients will proceed as follows: * If no DLT is reported at a dose level, that dose level will be considered safe, and patient(s) will be enrolled at the next dose level. Toxicity information will continue to be evaluated from the time of the first protocol specific intervention, until 30 days from the last dose of study drug. * If 1 patient in a cohort of 1 experiences a DLT, the dose level will be expanded to obtain an additional 2 evaluable patients. * If 1 patient in a cohort at a dose level experiences a DLT, the dose level will be expanded to obtain an additional 3 evaluable patients. * If 2 of 3 patients in a cohort at a dose level experience a DLT, that dose level will not be considered safe, no further dose escalation will take place, and the MTD will have been exceeded\*. * If 1 patient experiences a DLT among the expanded cohort of evaluable patients, a cohort of 3 patients will be enrolled in the next higher dose level. * If 2 or more patients experience a DLT among the expanded cohort of evaluable patients, that dose level will not be considered safe, no further dose escalation will take place, and the MTD will have been exceeded\*. The previous dose level at which ≤1 patients experienced a DLT will be declared the MTD. * When the MTD has been exceeded: If less than 6 patients have been treated in the next lower dose level (the possible MTD level), additional patients will be entered into this dose level until there are 6 patients treated. If ≤1 of these 6 patients encountered DLT, then this dose level will be declared to be the MTD. If 2 or more of the 6 patients encounter DLT, then the MTD has been exceeded. Given the experience with ONC201, it is possible a MTD may not be reached through the planned dose escalation cohorts. If the therapeutic target concentrations have been achieved in the dose escalation cohorts, and no DLT has been identified, then analysis of the safety and PK data will be evaluated by the Investigators and the Sponsor. Further dose levels may then be considered at higher intermittent dosing schedules and will be added by protocol amendment with review by the Institutional Review Board (IRB) before implementation. Toxicities will be graded using the Common Terminology Criteria for Adverse Events Version 24.0 (CTCAE 24.0). If the CTCAE 24.0 does not apply to an adverse event, it will be graded as mild, moderate, or severe. DLTs will be assessed during the first course of each cohort (28 days), and refers to a study drug related or possibly related event that meets 1 of the following criteria using the NCI CTCAE version 5.0: * Grade 3 or higher non-hematologic toxicity. * Grade 4 hematologic toxicity (ANC \<0.5 × 109/L and platelet count \<25 × 109/L). Lymphopenia is not considered a DLT. A confirmed DLT requires 2 consecutive measurements separated by 48 hours. * Grade 3 neutropenia (ANC \<1.0 × 109/L) with elevated fever (\>101°F). A confirmed DLT requires 2 consecutive measurements. * Grade 3 thrombocytopenia with clinically significant bleeding. * Inability to receive the scheduled Cycle 2, Day 1 dose of study drug within 14 days due to study drug-related toxicity persisting from Cycle 1 or study drug-related toxicity newly encountered on Day 1 of Cycle 2. Safety and tolerability will be monitored by assessing physical examinations including height (at Screening only) and weight, KPS, vital signs, ECG, laboratory assessments including hematology, chemistry, and coagulation, as well as collecting of the AEs at every visit.