ABT-888, Radiation Therapy, and Temozolomide in Treating Patients With Newly Diagnosed Glioblastoma Multiforme

DISEASE CHARACTERISTICS: * Histologically confirmed supratentorial grade IV astrocytoma (glioblastoma multiforme) * Newly diagnosed disease * Patients enrolled in the phase I initial safety portion of the study must meet the following additional criteria: * Received 90% of planned radiotherapy and ≥ 80% of planned concurrent temozolomide within the past 28-49 days * No grade 3-4 toxicity attributed to temozolomide * Has undergone gadolinium MRI or contrast CT scan within the past 28 days * Patients enrolled in the phase I dose-escalation/phase II portion of the study must meet the following additional criteria: * Recovered from immediate post-operative period and maintained on a stable corticosteroid regimen (no increase in 5 days) prior to starting study treatment * Has undergone gadolinium MRI or contrast CT scan within the past 14 days PATIENT CHARACTERISTICS: * Karnofsky performance status 60-100% * Life expectancy ≥ 3 months * ANC ≥ 1,500/mm\^3 * Platelet count ≥ 100,000/mm\^3 * Hemoglobin ≥ 9.0 g/dL * Creatinine ≤ 2.0 mg/dL OR creatinine clearance ≥ 60 mL/min * Total bilirubin ≤ 1.5 mg/dL * Transaminases ≤ 2.5 times upper limit of normal * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception prior to, during, and for 3 months after completion of study therapy * Mini Mental State Exam score ≥ 15 * Able to swallow and retain oral medications * No concurrent serious infection or medical illness that would jeopardize the ability of the patient to receive study treatment with reasonable safety * No other malignancy within the past 5 years except for curatively treated carcinoma in situ or basal cell carcinoma of the skin * No known uncontrolled seizure disorder (i.e., status epilepticus) or seizures occurring ≥ 3 times per week over the past month PRIOR CONCURRENT THERAPY: * See Disease Characteristics * More than 10 days since prior cytochrome P450-inducing anticonvulsants (e.g., phenytoin, carbamazepine, phenobarbital, primidone, or oxcarbazepine) * At least 1 week since prior biopsy or resection of tumor (for patients enrolled in the phase I dose-escalation/phase II portion of the study) * No prior radiotherapy, chemotherapy, immunotherapy, hormonal therapy, or biological therapy (including immunotoxins, immunoconjugates, antisense therapy, peptide receptor antagonists, interferons, interleukins, tumor-infiltrating lymphocytes, lymphokine-activated killer cells, or gene therapy) for treatment of brain tumor (for patients enrolled in the phase I dose-escalation/phase II portion of the study) * Prior glucocorticoid therapy allowed * No other prior chemotherapy or investigational agents (for patients enrolled in the phase I initial safety portion of the study) * Prior Gliadel wafers allowed (for patients enrolled in the phase I portion of the study) * No prior Gliadel wafers (for patients enrolled in the phase II portion of the study)