Inclusion Criteria:

- Histologically confirmed oligodendroglioma or mixed oligoastrocytoma

- Grade 2-4

- Recurrent disease

- Patients with mixed gliomas must have > 25% oligodendrogliomatous component

- Failed prior surgery, radiotherapy, and temozolomide or nitrosourea-based therapy

- Progressive disease by MRI or CT scan

- Measurable or evaluable disease by MRI or CT scan

- More than 2 prior chemotherapy regimens for progressive or recurrent disease (pilot
study only)

- Currently taking anticonvulsants which can induce cytochrome p450 (e.g., phenytoin,
carbamazepine, barbiturates, or primidone (Phase I only)

- No prior or concurrent significant intratumoral hemorrhage

- Performance status - ECOG 0-2

- Absolute neutrophil count at least 1,500/mm^3

- Platelet count at least 100,000/mm^3

- Hemoglobin at least 9 g/dL

- Bilirubin no greater than 1.5 mg/dL

- AST no greater than 3 times upper limit of normal

- Creatinine no greater than 2.0 mg/dL

- No myocardial infarction within the past 6 months

- No congestive heart failure requiring maintenance therapy for life-threatening
ventricular arrhythmias

- No New York Heart Association class III or IV heart disease

- No active uncontrolled infection

- No other severe concurrent disease that would preclude study or interfere
significantly with interpreting potential drug-induced toxic effects

- No other active malignancy except nonmelanoma skin cancer

- No concurrent serious immunocompromised status unless related to concurrent steroids

- HIV-positive patients allowed

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception during and for 6 months after study
participation

- At least 2 weeks since prior biologic noncytotoxic agents (e.g., thalidomide or
interferon)

- No concurrent biologic therapy or immunotherapy for brain cancer

- No concurrent therapeutic warfarin or heparin

- Low-dose warfarin and heparin (1 mg daily) allowed

- No prior interstitial chemotherapy, including carmustine wafers, unless separate
lesion seen on MRI outside of prior treatment field

- At least 2 weeks since prior vincristine

- At least 4 weeks since other prior chemotherapy (6 weeks for nitrosoureas)

- No concurrent chemotherapy for brain cancer

- At least 2 weeks since prior tamoxifen

- Concurrent corticosteroids allowed if dose stable for at least 1 week prior to study
entry

- No concurrent hormonal therapy for brain cancer

- At least 12 weeks since prior radiotherapy

- No prior stereotactic radiosurgery or interstitial brachytherapy unless separate
lesion seen on MRI outside of prior treatment field

- No concurrent radiotherapy for brain cancer

- No other concurrent investigational or noninvestigational therapy for brain cancer

- At least 2 weeks since prior surgery for initial or progressive disease and recovered

- No concurrent surgery for brain cancer

- At least 2 weeks since prior isotretinoin

- At least 4 weeks since prior investigational agents