PS-341 in Treating Patients With Metastatic Neuroendocrine Tumors

DISEASE CHARACTERISTICS: Histologically confirmed metastatic carcinoid tumor or islet cell tumor Well-differentiated neuroendocrine tumor OR Well-differentiated neuroendocrine carcinoma Measurable disease in at least 1 dimension At least 20 mm by conventional techniques OR at least 10 mm by spiral CT scan The following are considered nonmeasurable: Lesions in a previously irradiated area Bone lesions Leptomeningeal disease Ascites Pleural/pericardial effusion Lymphangitis cutis/pulmonis Abdominal masses that are not confirmed and followed Cystic lesions PATIENT CHARACTERISTICS: Age: 18 and over Performance status: ECOG 0-2 Life expectancy: At least 6 months Hematopoietic: Leukocyte count at least 3,000/mm^3 Absolute neutrophil count at least 1,500/mm^3 Platelet count at least 100,000/mm^3 Hepatic: Bilirubin no greater than 1.5 mg/dL AST/ALT no greater than 2.5 times upper limit of normal Renal: Creatinine no greater than 1.5 mg/dL Cardiovascular: No symptomatic congestive heart failure No unstable angina pectoris No cardiac arrhythmia Other: No other uncontrolled illness No ongoing active infection No psychiatric illness or social situation that would preclude study No history of allergic reaction to compounds of similar chemical or biologic composition to bortezomib Not pregnant or nursing Negative pregnancy test Fertile patients must use effective contraception PRIOR CONCURRENT THERAPY: Biologic therapy: At least 4 weeks since prior immunotherapy (interferon alfa) Chemotherapy: No more than 1 prior systemic chemotherapy regimen (except hepatic artery chemoembolization) At least 4 weeks since prior systemic chemotherapy (6 weeks for nitrosoureas) At least 12 weeks since prior hepatic artery chemoembolization (unless liver lesions are not indicator lesions) Stable dose long-acting octreotide therapy (Sandostatin LAR) within the past 3 months allowed Concurrent subcutaneous octreotide for breakthrough symptomatic relief allowed Endocrine therapy: Not specified Radiotherapy: See Disease Characteristics At least 4 weeks since prior radiotherapy Surgery: Not specified Other: No other concurrent investigational agents, commercial agents, or therapies No concurrent combination antiretroviral therapy for HIV-positive patients