Inclusion Criteria:

- Histologically confirmed grade 4 astrocytoma at primary diagnosis or recurrence

- Gliosarcoma allowed

- Evidence of tumor progression by MRI or CT scan after radiotherapy or first-line
chemotherapy

- Measurable or evaluable disease by MRI or CT scan

- 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

- SGOT 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 ongoing maintenance therapy for
life-threatening ventricular arrhythmias

- Cholesterol no greater than 350 mg/dL

- Triglycerides no greater than 400 mg/dL

- Willing to provide correlative laboratory samples

- No uncontrolled infection

- No known hypersensitivity to any components of CCI-779, diphenhydramine
hydrochloride, or other similar antihistamines

- No other medical reason that would preclude diphenhydramine premedication

- No other active malignancy

- No other severe disease that would preclude study participation

- Not immunocompromised unless due to corticosteroids

- HIV negative

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception

- See Disease Characteristics

- Prior adjuvant chemotherapy allowed

- More than 4 weeks since prior chemotherapy (6 weeks for nitrosoureas)

- No more than 1 prior chemotherapy regimen for recurrent/progressive disease

- No prior polifeprosan 20 with carmustine implant (Gliadel)

- Must be on fixed dose of corticosteroids (or no corticosteroids) at least 1 week
prior to baseline scan

- See Disease Characteristics

- At least 12 weeks since prior radiotherapy

- No prior stereotactic radiosurgery or interstitial brachytherapy unless there is a
separate lesion on MRI that is outside of the previously treated field

- No prior resection since last chemotherapy or radiotherapy unless there is
unequivocal tumor growth on neuro-imaging study since surgery or there is a separate
lesion not present in the surgical bed

- More than 4 weeks since prior investigational agents