• Participants between the ages of 18 and 50 years with pathologically-confirmed diagnosis of (or pathology re-review consistent with) DHG will be enrolled in this study

• A female participant who has childbearing potential must have negative urine or serum pregnancy test 72 hours prior to the first dose and be willing to use adequate method of contraception for course of study and 120 days after last dose

• The participant (or legally acceptable representative if applicable) provides informed consent (and written assent from minors) for the trial

• An interval of the following durations prior to enrollment:

‣ At least 28 days from prior surgical resection

⁃ At least 14 days from prior stereotactic biopsy

• Have clinical pathology results, commercial targeted exome sequencing results, or sufficient archival tumor tissue to confirm DHG following registration. The following amount of tissue is preferred: 25-50 mg flash frozen tissue block. Formalin-fixed, paraffin embedded (FFPE) tissue block or 10 FFPE unstained slides (5µm thick) is acceptable at the discretion of the Sponsor-Investigator

• Have a Karnofsky performance status (KPS) ≥ 70

• Absolute neutrophil count (ANC) ≥ 1500/uL (specimens must be collected within 14 days prior to the start of study treatment)

• Platelets ≥ 100 000/µL (specimens must be collected within 14 days prior to the start of study treatment)

• Hemoglobin ≥ 9.0 g/dL or ≥ 5.6 mmol/L (specimens must be collected within 14 days prior to the start of study treatment)

‣ Criteria must be met without erythropoietin dependency and without packed red blood cell (pRBC) transfusion within last 2 week

• Creatinine or measured or calculated b creatinine clearance (GFR can also be used in place of creatinine or CrCl) ≤ 1.5 × ULN or ≥ 30 mL/min for participant with creatinine levels \> 1.5 × institutional ULN (specimens must be collected within 14 days prior to the start of study treatment)

‣ Creatinine clearance (CrCl) should be calculated per institutional standard.

• Total bilirubin ≤ 1.5 ×ULN or direct bilirubin ≤ ULN for participants with total bilirubin levels \>1.5 × ULN (specimens must be collected within 14 days prior to the start of study treatment)

• Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase \[SGOT\]) and alanine aminotransferase (ALT) (serum glutamate pyruvate transaminase \[SGPT\]) ≤ 2.5 × ULN (≤ 5 × ULN for participants with liver metastases) (specimens must be collected within 14 days prior to the start of study treatment)

• International normalized ratio (INR) OR prothrombin time (PT) activated partial thromboplastin time (aPTT) ≤ 1.5 × ULN unless participant is receiving anticoagulant therapy as long as PT or aPTT is within therapeutic range of intended use of anticoagulants (specimens must be collected within 14 days prior to the start of study treatment)