Valproic Acid in Treating Patients With Kaposi's Sarcoma

DISEASE CHARACTERISTICS: * Histologically confirmed HIV-related Kaposi's sarcoma (KS) * Disease involving the skin and/or lymph nodes * No symptomatic visceral disease * No oral KS as the only site of disease * Slowly progressive or stable disease allowed * Slow progression defined as fewer than 5 new lesions per month * Must have documented HIV infection by positive ELISA, western Blot, or viral load determination * CD4 T-cell count \> 50/mm\^3 PATIENT CHARACTERISTICS: Age * 18 and over Performance status * Karnofsky 60-100% Life expectancy * At least 3 months Hematopoietic * Hemoglobin ≥ 8.0 g/dL * Absolute neutrophil count ≥ 750/mm\^3 * Platelet count ≥ 75,000/mm\^3 Hepatic * Bilirubin ≤ 1.5 times upper limit of normal (ULN)\* * AST and ALT ≤ 3 times ULN * Albumin \> 2.5 g/dL NOTE: \*Elevated total bilirubin (≤ 3.5 mg/dL) secondary to indinavir therapy allowed provided the direct bilirubin is normal Renal * Creatinine \< 1.5 times ULN Cardiovascular * No prior myocardial infarction * No evidence of cardiac ischemia Other * Not pregnant * Negative pregnancy test * Fertile patients must use effective contraception during and for 3 months after study participation * No prior lactic acidosis \> 2.0 mmoles/L * No prior lipoatrophy or hypercholesterolemia secondary to retroviral treatment * No concurrent, acute, active opportunistic infection other than oral thrush or genital herpes within the past 14 days * No other concurrent neoplasm requiring cytotoxic therapy PRIOR CONCURRENT THERAPY: Biologic therapy * More than 2 weeks since prior biologic therapy for KS Chemotherapy * More than 2 weeks since prior chemotherapy for KS * No concurrent systemic cytotoxic chemotherapy Endocrine therapy * Not specified Radiotherapy * More than 2 weeks since prior radiotherapy for KS Surgery * Not specified Other * More than 2 weeks since other prior antineoplastic or local therapy for KS * More than 2 weeks since prior investigational therapy for KS * More than 60 days since prior local therapy to a KS-marker lesion unless lesion has clearly progressed since therapy * More than 1 year since prior valproic acid * Concurrent antiretroviral therapy allowed provided regimen has been stable for at least 4 weeks * No concurrent zidovudine * No other concurrent KS-specific therapy * No other concurrent investigational drugs, other than IND-approved antiretroviral agents