Methimazole in Patients With Progressive Glioblastoma

The purpose of this study is to test the effectiveness, safety, and tolerability of a drug called Methimazole. The investigational drug, Methimazole is not FDA approved for brain tumors, but it is used to treat thyroid illnesses. Different doses of Methimazole will be given to several study participants with glioblastoma. The first several study participants will receive the lowest dose. If the drug does not cause serious side effects, it will be given to other study participants at a higher dose. The doses will continue to increase for every group of study participants until the side effects occur that require the dose to be lowered. The procedures in this study are research blood draws, physical exams, collection of medical history, MRI scans, and study drug administration.

Inclusion Criteria: * Subjects must have histologically or cytologically confirmed WHO grade 4 glioma (including tumors with molecularly defined grade 4 astrocytoma) for which a clinically indicated tumor resection is planned. * Subjects must not have received methimazole for this disease. * Age is greater than or equal to 18 years of age * Performance status: Karnofsky Performance status ≥ 70% * Subjects must have adequate organ function and laboratory parameters within 21 days of study entry as defined below: Hemoglobin ≥ 8 g/dl, Absolute neutrophil count ≥ 1,200/mcL, Platelet count ≥ 75,000/mcL, Total bilirubin \< 1.5 x institutional upper limit of normal (ULN), AST (SGOT) ≤ 3 X institutional ULN, ALT (SGPT) ≤ 3 X institutional ULN, Calculated creatinine clearance \> 50 mL/min, Prothrombin time/international normalized ratio (PT/INR) \