DISEASE CHARACTERISTICS:

• Histologically confirmed supratentorial glioblastoma multiforme

  • Progressive or recurrent disease after prior radiotherapy (with or without chemotherapy)
  • Patients with a previous low-grade glioma that progressed after prior radiotherapy (with or without chemotherapy) and are found to have glioblastoma by biopsy are eligible
• Patients must have tumor tissue form completed and signed by a pathologist
• Measurable disease, defined as contrast-enhancing progressive or recurrent glioblastoma multiforme by MRI or CT scan within the past 2 weeks

PATIENT CHARACTERISTICS:

• Karnofsky performance status 60-100%
• ANC ≥ 1,500/mm³
• Platelet count ≥ 100,000/mm³
• Creatinine ≤ 1.5mg/dL
• Total bilirubin ≤ 1.5mg/dL
• ALT and AST ≤ 2.5 times upper limit of normal
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use adequate contraception before, during, and for at least one month after the last dose of R-(-)-gossypol
• Mini Mental State Exam score ≥ 15

• No serious concurrent infection or medical illness that would jeopardize the ability of the patient to receive the study treatment with reasonable safety, including, but not limited to, any of the following:

  • Uncontrolled hypertension
  • Symptomatic congestive heart failure
  • Unstable angina pectoris
  • Cardiac arrhythmia
• No psychiatric illness or social situation that would limit study compliance
• No allergic reaction to gossypol

• No other prior malignancy except curatively treated carcinoma in situ or basal cell carcinoma of the skin

  • Patients with a prior malignancy are ineligible unless they have been free of disease for ≥ 5 years
• No sensory neuropathy ≥ grade 2
• No condition (e.g., gastrointestinal tract disease resulting in an inability to take oral medication or a requirement for IV alimentation, or active peptic ulcer disease) that impairs ability to swallow pills
• No malabsorption syndrome, disease significantly affecting gastrointestinal function, or resection of the stomach or small bowel
• No ulcerative colitis, inflammatory bowel disease, or partial or complete small bowel obstruction
• No symptomatic hypercalcemia > grade 2

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics
• Recovered from prior therapy
• At least 3 months since prior radiotherapy
• At least 3 weeks since prior chemotherapy (6 weeks for nitrosoureas)
• At least 3 weeks since prior investigational, non-cytotoxic agents
• At least 2 weeks since prior non-cytotoxic, FDA approved agents (e.g., celecoxib or thalidomide)
• No more than two prior treatments
• No prior R-(-)-gossypol
• No prior surgical procedures affecting absorption
• No other concurrent chemotherapeutic or investigational agents for glioblastoma multiforme
• No concurrent iron supplements
• No concurrent cytochrome P450-inducing anticonvulsant drugs that induce hepatic metabolic enzymes (i.e., enzyme-inducing antiepileptic drugs) such as (e.g., phenytoin, carbamazepine, phenobarbital, primidone, or oxcarbazepine)
• No requirement for routine use of hematopoietic growth factors (e.g., filgrastim [G-CSF], sargramostim [GM-CSF]), or interleukin-11) or platelet transfusions to maintain absolute neutrophil counts or platelet counts above the required thresholds for study entry
• No concurrent prophylactic hematopoietic growth factors (G-CSF, GM-CSF, or IL-11) during the first course of treatment
• No concurrent combination antiretroviral therapy for HIV-positive patients
• No concurrent drugs, foods, supplements, or over-the-counter medications containing divalent cations (e.g., dairy products, calcium supplements, or antacids for 2 hours before to 4 hours after each dose of study drug
• Concurrent steroids allowed