DISEASE CHARACTERISTICS:

• Biopsy-proven cutaneous AIDS-related Kaposi sarcoma (KS)

  • Relapsed after or refractory to liposomal anthracycline

    • Relapsed after or refractory to other agents (in addition to liposomal anthracycline) allowed
• Cutaneous KS lesion(s) amenable to biopsy (either one lesion ≥ 12 mm or 3 lesions ≥ 4 mm) AND has ≥ 5 lesions measurable for assessment

• Has been on stable anti-retroviral therapy for ≥ 12 weeks that includes a protease inhibitor-based or non-nucleoside reverse transcriptase inhibitor-based regimen of ≥ 3 drugs AND has no intention to change the regimen for the duration of the study

  • Patients who have a high likelihood of better HIV management with a new antiretroviral regimen should defer study enrollment until the changes are in place and the new HAART regimen meets the 12-week criteria
• Serologic documentation of HIV infection, as evidenced by positive ELISA, positive western blot, or other FDA-approved licensed HIV test OR by a detectable blood level of HIV RNA
• No KS that is improving within the past 4 weeks
• No symptomatic visceral KS (oral and lymph node involvement are allowed)
• No pulmonary KS by chest x-ray or chest CT scan unless bronchoscopy does not confirm KS

PATIENT CHARACTERISTICS:

• ECOG performance status 0-2
• Life expectancy ≥ 3 months
• Platelet count ≥ 100,000/mm³
• ANC ≥ 1,000/mm³*
• Hemoglobin ≥ 8.0 g/dL*
• Total bilirubin ≤ 1.5 mg/dL**
• AST and ALT ≤ 2.5 times upper limit of normal
• Serum creatinine normal OR creatinine clearance ≥ 50 mL/min
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for up to 3 months after the completion of study treatment
• No herpes zoster (shingles) outbreak within the past 6 months or inability to take herpes zoster prophylaxis
• No concurrent active opportunistic infection
• No acute infection or other serious medical illness that has required treatment within the past 14 days
• No pre-existing grade 3 or 4 peripheral neuropathy
• No other primary malignancies within the past 5 years, unless the primary malignancy is neither currently clinically significant nor requires active intervention OR the primary malignancy is basal cell skin cancer or cervical/anal carcinoma in situ
• No physical or psychiatric condition that, in the opinion of the investigator, would place the patient at high risk for toxicity or non-compliance
• No hypersensitivity to boron
• No grade III/IV cardiac disease, as defined by the New York Hearth Association Criteria (e.g., congestive heart failure or myocardial infarction within the past 6 months)

• No acute or known chronic liver disease (e.g., chronic active hepatitis or cirrhosis)

  • Patients with known hepatitis B or C infection may be enrolled if they have either documentation of no or minimal fibrosis on liver biopsy or undetectable hepatitis virus on PCR NOTE: *Growth factor support allowed

NOTE: **If the elevated bilirubin is felt to be secondary to indinavir or atazanavir therapy, then patients will be allowed on study without any limit on the total bilirubin provided the direct bilirubin is normal.

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics
• More than 4 weeks since prior anti-neoplastic therapy for KS, including chemotherapy (6 weeks for nitrosourea or mitomycin C), radiotherapy, biological therapy, or investigational therapy
• More than 60 days since prior local therapy for any KS indicator lesion, unless the lesion has clearly progressed with enlargement since the local therapy
• More than 4 weeks since prior and no other concurrent investigational drugs (other than antiretroviral agents obtained through an expanded access protocol)
• No prior bortezomib or other investigational proteasome inhibitors
• No prior radiotherapy to study lesions
• No concurrent systemic corticosteroid therapy (other than replacement doses for adrenal insufficiency)
• No concurrent topical agents to study lesions
• No concurrent cidofovir, voriconazole, itraconazole, cisapride, diltiazem, erythromycin, rifampin, rifabutin, St. John's wort, or ketoconazole
• No concurrent systemic cytotoxic chemotherapy, biological therapy, or any other treatment specifically prescribed to treat KS (e.g., radiotherapy)
• No grapefruit juice for 24 hours before and for 72 hours after bortezomib dosing
• No concurrent green tea