Enzastaurin and Temozolomide in Treating Patients With Primary Gliomas

DISEASE CHARACTERISTICS: * Histologically confirmed primary supratentorial glioma * WHO histologic grade 3 or 4 * Patients who have undergone prior treatment for low-grade glioma that has transformed to glioblastoma (biopsy proven) allowed * Amenable to standard temozolomide treatment * First or second recurrent disease after prior surgery and/or radiotherapy OR newly diagnosed disease that is not amenable to radiotherapy (e.g., multifocal disease) PATIENT CHARACTERISTICS: * ECOG or WHO performance status 0-2 * Hemoglobin ≥ 10.0 g/dL * Neutrophil count ≥ 1,500/mm\^3 * Platelet count ≥ 100,000/mm\^3 * Bilirubin ≤ 1.5 x upper limit of normal (ULN) * Alkaline phosphatase and transaminases ≤ 2.5 x ULN * Serum creatinine \< 1.7 mg/dL * Not pregnant or lactating * Negative pregnancy test * Fertile patients must use effective contraception * Clinically normal cardiac function * No ischemic heart disease within the past 6 months * No clinically significant abnormalities or uncontrolled cardiac arrhythmia by ECG * QTc interval ≤ 450 msec (males) or ≤ 470 msec (females) by baseline 12-lead ECG * No history of congenital long QTc syndrome * No history of stroke * No other prior or concurrent malignancy within the past 5 years except cone biopsied carcinoma of the cervix or adequately treated basal or squamous cell skin carcinoma * No unstable systemic diseases * No active uncontrolled infections * No uncontrolled hypertension * No psychological, familial, sociological, or geographical condition that would preclude study participation * Must be able to swallow tablets PRIOR CONCURRENT THERAPY: * See Disease Characteristics * No more than 1 prior chemotherapy regimen in the adjuvant setting or for first recurrence * Prior temozolomide allowed provided there was no disease progression during temozolomide treatment or within 6 weeks of completing temozolomide treatment * Prior surgery for primary brain tumor within the past 3 months allowed * Patients who are receiving corticosteroid treatment must be on a stable or decreasing dose for at least 1 week before study entry * At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas) * At least 14 days since prior and no concurrent enzyme-inducing antiepileptic drugs including, but not limited to, any of the following: * Phenytoin * Carbamazepine * Phenobarbital * More than 30 days since prior and no other concurrent investigational treatments * No concurrent anticoagulant treatment (e.g., warfarin) * Low molecular weight heparin for patients who require anticoagulant therapy after starting study treatment may be allowed * No concurrent routine use of colony-stimulating factors * No other concurrent anticancer agents