Age ? 18 years at time of informed consent Parts A & C: patients must be >= 12 months and < 18 years of age at the time of study enrollment Parts B1-B6, B8, D1-D6, E3, E4: patients must be >= 12 months and =< 30 years of age at the time of study enrollment Part B7: patients must be >= 12 months and < 18 years of age at the time of study enrollment Part A1: Patients must be >= 12 months and =< 21 years of age at the time of study enrollment Efficacy Phase: Patients must be =< 40 years of age at the time of enrollment Must be less than 30 years of age at time of original diagnosis Male or female participants age ?18 years (or any age ?18 years if that age is considered to be an adult per the local jurisdiction) at the time of informed consent 18 years of age at the time of consenting. Subjects must be at least 1 and less than or equal to 18 years of age at the time of study entry. Age ? 18.0 years and < 66.0 years at the time of enrollment. Patient is < 75 years of age at time of enrollment. Age: ? 21 years at the time of study entry. Patients must be less than 18 years of age at the time of diagnosis. Age >= 1 year and < 25 years at the time of screening; exception: participants with recurrent, progressive, or refractory medulloblastoma and are >= 1 and < 40 years of age at the time of study screening are eligible for screening STRATUM A: Age >= 1 year and < 25 years at the time of screening STRATUM B: Age >= 1 year and < 25 years at the time of study enrollment STRATUM C: Age >= 10 years and < 40 years at the time of study enrollment Age ?18 years at the time of informed consent. Age >18 years and ? 70 years at the time of enrollment Be ? 18 years of age at time of consent Patient is at least 18 years of age and <90 years of age at the time Informed Consent is signed. Age ?18 years at the time of informed consent Age ? 18 years at the time of consent. Age:\r\n* Phase 1: >= 6 and =< 21 years of age at time of enrollment\r\n* Phase 2: >= 6 and =< 21 years of age at diagnosis Age (at the time of consent/assent): ?16 years of age Female subjects who are at least 18 years of age at the time of informed consent Age > 18 years at time of study entry Patients must be > than 12 months and ? 21 years of age at the time of study enrollment. Age: ? 21 years at the time of diagnosis. Any patient with both metastatic ependymoma and age < 3 years at the time of enrollment Age ? 18 years at the time of screening or age of consent according to local law Stratum 1 (IDH wild-type): Patients must be >= 3 years of age and =< 21 years of age at the time of enrollment Stratum 2 (IDH mutant): Patients must be >= 3 years of age and =< 25 years of age at the time of enrollment 102 Age ? 18 at the time of informed consent. Age ?18 years at the time of consent. Males >=18 years of age (at the time written consent is obtained for screening) The subject must be >= 12 years of age at the time of consent Age:\r\n* Part A1: Patients must be >= 12 months and < 18 years of age at the time of study enrollment\r\n* Part A2: Patients must be > 6 months and < 12 months of age at the time of study enrollment; patients will enroll one dose level behind the dose level at which patients in Part A1 are enrolling Age:\r\n* Phase 1 (Part A)\r\n** Patients must be > than 12 months and =< 21 years of age at the time of study enrollment\r\n* Phase 2 (Part B and Part C)\r\n** Patients must be > than 12 months and =< 30 years of age at the time of study enrollment Age (at the time of consent/assent): ?6 months to ?21 years Age 3 at the time of initial diagnosis to age 21 at the time of initial diagnosis Age 3 at the time of screening to age 21 at the time of initial diagnosis Age ? 18 at time of informed consent Age (at the time of consent) ?18 years of age Age ?18 years at the time of screening Patients must be ? 12 months of age and ? 30 years of age at the time of study entry for patients diagnosed with DIPG. Patients must be ? 12 months of age and ? 21 years of age at the time of study entry for patients diagnosed with HGG. Men ? 18 years of age at the time of informed consent. Are at least 18 years of age at the time of informed consent Age > 18 years at the time of consent. Lansky (age < 16 years at the time of assent/consent) or Karnofsky (age ? 16 years at the time of assent/consent) performance status ? 80 at screening Age ? 18 years at the time of consent ? 18 years at time of consent. Age 21 years or younger at the time of initial ALL diagnosis and age > 1 year at the time of study treatment initiation. Age ? 18 years at the time of consent. Age: >=18 years of age at the time of providing informed consent. Males and female subjects ? 18 years of age at the time of enrollment, except in Japan where subjects must be ? 20 years of age at the time of enrollment Age 60-75 years at the time of diagnosis of AML 6 months to less than 18 years of age at the time of consent. Female gender and age ? 18 years at time of study entry Age >=18 years at the time of consent. Be ? 18 years of age at time of consent Age ? 18 years at the time of consent. Age ? 18 years at the time of consent Patients must be ? 21 years of age at the time of enrollment. Be at least 18 years of age at the time of consent At least 18 years of age at time of study entry Age ? 18 years of age, at the time of informed consent. Males >=18 years of age (at the time consent is obtained) The patient is >= 18 years of age at the time of signature of the first informed consent form. Age > 18 years at the time of consent. The patient is >= 18 years of age at the time of signature of the informed consent form. Age ? 18 years at the time of screening. The child is 3-8 years of age at time of enrollment Age > 18 years at the time of consent. Age 5-17 years at time of study enrollment Age: 0-21 years at the time of diagnosis. Age: 0-21 years at the time of diagnosis. Age: 0-21 years at the time of diagnosis. Is 0 (at least 37 weeks gestation) to 17 years of age at time of randomization Between 4.0 years and < 11.0 years of age at the time of recruitment Is at least 18 years of age at the time of consent Age: >1 month and <30 years at time of enrollment Age ? 18 years at time of consent (19 years if required by local or state laws)