Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically confirmed malignant glioma

- Anaplastic astrocytoma

- Anaplastic oligodendroglioma

- Glioblastoma multiforme

- Anaplastic mixed oligoastrocytoma

- Progressive or recurrent disease* after radiotherapy with or without chemotherapy
NOTE: *Patients with prior low-grade glioma who progressed after therapy and are
found to have high-grade glioma are eligible

- Measurable disease by MRI or CT scan

PATIENT CHARACTERISTICS:

Age

- 18 and over

Performance status

- Karnofsky 60-100%

Life expectancy

- More than 2 months

Hematopoietic

- Absolute neutrophil count ≥ 1,500/mm^3

- Platelet count ≥ 100,000/mm^3

Hepatic

- Bilirubin ≤ 1.5 mg/dL

- Transaminases ≤ 4 times upper limit of normal

Renal

- Creatinine ≤ 1.7 mg/dL

Other

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use 1 highly active method and 1 additional effective method of
contraception for 1 month before, during, and for 4 weeks after study treatment

- No concurrent serious infection

- No other concurrent medical illness that would preclude study treatment

- No other malignancy within the past 5 years except curatively treated carcinoma in
situ of the cervix or basal cell skin cancer

PRIOR CONCURRENT THERAPY:

Biologic therapy

- No prior thalidomide

- No concurrent prophylactic filgrastim (G-CSF)

Chemotherapy

- See Disease Characteristics

- At least 3 weeks since prior chemotherapy (6 weeks for nitrosoureas)

- No prior procarbazine

- No more than 2 prior chemotherapy regimens for malignant glioma

Endocrine therapy

- Not specified

Radiotherapy

- See Disease Characteristics

- At least 3 months since prior radiotherapy

Other

- Recovered from prior therapy

- More than 7 days since prior antidepressants (selective serotonin reuptake inhibitors
and/or monamine oxidase inhibitors)

- No concurrent antidepressants

- No other concurrent investigational agents