Gemcitabine Hydrochloride in Treating Patients with Diffuse Midline Glioma

Inclusion Criteria

• Age greater than or equal to 3 years and less than 18 years at the time of enrollment
• Patients must meet both of the first two conditions, OR the third: * Clinical findings consistent with a presumed new diagnosis of diffuse midline glioma (DMG) in the opinion of the treating neuro-oncologist, AND * Brain magnetic resonance imaging (MRI) findings consistent with a new diagnosis of DMG based on multidisciplinary consensus after review of imaging * OR, recurrent DMG requiring tumor resection or biopsy
• Platelet count >= 100,000/ul (no platelet transfusion for more than 3 days)
• Hemoglobin > 8 g/dl
• Absolute neutrophil count (ANC) >= 1,000/ul
• Prothrombin time (PT) and activated partial thromboplastin time (aPTT) =< upper limit of normal (ULN) for age
• Creatinine clearance or radioisotope glomerular filtration rate (GFR) >= 70 ml/min/1.73 m^2 or
• A serum creatinine based on age/gender as follows: maximum serum creatinine (mg/dL) * 3 to < 6 years: 0.8 (male and female) * 6 to < 10 years: 1 (male and female) * 10 to < 13 years: 1.2 (male and female) * 13 to < 16 years: 1.5 (male) 1.4 (female) * 16 to < 18 years: 1.7 (male) 1.4 (female)
• Total bilirubin < 3 x ULN for age
• Serum glutamic-oxaloacetic transaminase (SGOT) (aspartate aminotransferase [AST]) and serum glutamate pyruvate transaminase (SGPT) (alanine aminotransferase [ALT]) < 2.5 x ULN for age
• Patients must meet one of the following performance scores: * Eastern Cooperative Oncology Group (ECOG) performance status scores of 0, 1, or 2; * Karnofsky score of >= 60 for patients > 16 years of age; or * Lansky score of >= 60 for patients =< 16 years of age
• DMG biopsy/resection is planned for the clinical care of the patient independent of study participation by the treating pediatric neurosurgeon and neuro-oncologist
• Informed consent and assent obtained as appropriate

Exclusion Criteria

• Pregnant or breastfeeding patients are not eligible
• Patients who have received any tumor-directed therapy prior to biopsy are not eligible; concurrent treatment with corticosteroids is allowed
• Any tumor-specific or clinical features that make surgical intervention unsafe in the opinion of the treating neurosurgeon
• Patients with personal or family history of bleeding disorders are not eligible
• Patients with uncontrolled intercurrent illness including, but not limited to ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements are not eligible