Inclusion Criteria:

          -  Histologically or cytologically confirmed diagnosis of advanced and unresectable or
             metastatic solid malignancy

          -  Measurable disease as defined by Response Evaluation Criteria in Solid Tumors, Version
             1.1 (RECIST v1.1), Response Assessment in Neuro-Oncology (RANO) criteria, or
             International Neuroblastoma Response Criteria (INRC)

          -  Performance status as follows: Participantss aged >= 18 years: Eastern Cooperative
             Oncology Group (ECOG) Performance Status 0-2; Participantss aged 16 to < 18 years:
             Karnofsky score >= 50%; Participants aged < 16 years: Lansky score >= 50%

          -  For participants aged >= 18 and <18 years: adequate hematologic and end-organ function

          -  Disease progression on prior treatment, or previously untreated disease with no
             available acceptable treatment

          -  Adequate recovery from most recent systemic or local treatment for cancer

          -  Life expectancy >= 8 weeks

          -  Ability to comply with the study protocol, in the investigator's judgment

          -  For female participants of childbearing potential: Negative serum pregnancy test <= 14
             days prior to initiating study treatment; agreement to remain abstinent or use single
             or combined contraception methods that result in a failure rate of < 1% per year for
             the period defined in the cohort-specific inclusion criteria; and agreement to refrain
             from donating eggs during the same period

          -  For male participants: Willingness to remain abstinent or use acceptable methods of
             contraception as defined in the cohort-specific inclusion criteria

          -  In addition to the general inclusion criteria above, participants must meet all of the
             cohort-specific inclusion criteria for the respective cohort

        Exclusion Criteria:

          -  Current participation or enrollment in another therapeutic clinical trial

          -  Any anticancer treatment within 2 weeks or 5 half-lives prior to start of study
             treatment

          -  Whole brain radiotherapy within 14 days prior to start of study treatment

          -  Stereotactic radiosurgery within 7 days prior to start of study treatment

          -  Pregnant or breastfeeding, or intending to become pregnant during the study

          -  History of or concurrent serious medical condition or abnormality in clinical
             laboratory tests that, in the investigator's judgment, precludes the participant's
             safe participation in and completion of the study or confounds the ability to
             interpret data from the study

          -  Incomplete recovery from any surgery prior to the start of study treatment that would
             interfere with the determination of safety or efficacy of study treatment

          -  Significant cardiovascular disease, such as New York Heart Association cardiac disease
             (Class II or higher), myocardial infarction, or cerebrovascular accident within 3
             months prior to enrollment, unstable arrhythmias, or unstable angina

          -  History of another active cancer within 5 years prior to screening that may interfere
             with the determination of safety or efficacy of study treatment with respect to the
             qualifying solid tumor malignancy

          -  In addition to the general exclusion criteria above, in order to be enrolled in a
             treatment cohort of the study, participants must not meet any of the cohort-specific
             exclusion criteria