Imatinib Mesylate in Treating Patients With HIV-Related Kaposi's Sarcoma

DISEASE CHARACTERISTICS: Histologically confirmed Kaposi's sarcoma (KS) involving at least 1 of the following areas: Skin Lymph nodes Oral cavity Gastrointestinal tract* Lungs* NOTE: *Must be asymptomatic or minimally symptomatic AND does not require systemic cytotoxic therapy Serological documentation of HIV infection, as evidenced by positive enzyme-linked immunosorbent assay (ELISA), Western Blot test, or other federally approved licensed HIV test At least 5 measurable, non-irradiated, cutaneous indicator lesions Patients must have 3 lesions at least 5 x 5 mm that are accessible for 4 mm punch biopsy 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 ≥ 1,000/mm^3 Platelet count ≥ 75,000/mm^3 Hepatic AST and ALT ≤ 2.5 times upper limit of normal Bilirubin normal Patients with elevated bilirubin secondary to indinavir or atazanavir allowed provided total bilirubin is < 3.5 mg/dL AND direct bilirubin is normal No acute or known chronic liver disease (e.g., chronic active hepatitis or cirrhosis) Hepatitis C infection with minimal or no fibrosis on liver biopsy allowed Renal Creatinine ≤ 1.5 mg/dL OR Creatinine clearance > 60 mL/min Cardiovascular No New York Heart Association class III or IV cardiac disease No congestive heart failure No myocardial infarction within the past 6 months Other Not pregnant or nursing Negative pregnancy test Fertile patients must use effective barrier contraception during and for 3 months after study participation No concurrent active opportunistic infection No other severe and/or life-threatening medical disease No other malignancy within the past 5 years except clinically insignificant malignancy not requiring active intervention, basal cell skin cancer, or carcinoma in situ of the cervix PRIOR CONCURRENT THERAPY: Biologic therapy More than 4 weeks since prior biologic therapy for KS More than 2 weeks since prior granulocyte colony-stimulating factor No concurrent biologic agents for KS Chemotherapy More than 4 weeks since prior chemotherapy for KS (6 weeks for nitrosoureas or mitomycin) No concurrent chemotherapy for KS, including systemic cytotoxic chemotherapy Endocrine therapy No concurrent systemic corticosteroid therapy except replacement doses Radiotherapy See Disease Characteristics More than 4 weeks since prior radiotherapy for KS No concurrent radiotherapy for KS Surgery More than 2 weeks since prior major surgery Other No prior imatinib mesylate More than 60 days since prior local therapy to any KS indicator lesion unless the lesion has progressed since treatment More than 4 weeks since prior investigational therapy for KS More than 4 weeks since other prior therapy for KS More than 14 days since prior acute treatment for an infection or other serious medical illness No concurrent warfarin No concurrent grapefruit juice No other concurrent therapy for KS No other concurrent investigational drugs Concurrent antiretroviral therapy required except for patients who have exhausted all available treatment options