DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed neuroendocrine tumor

  • Carcinoid histology OR carcinoma of pancreatic islet cell origin

    • No small cell variant, endocrine organ carcinomas, or adrenal gland malignancies (including paragangliomas)
  • Metastatic disease

• Measurable disease

  • At least 1 unidimensionally measurable lesion ≥ 20 mm by conventional techniques OR ≥ 10 mm by spiral CT scan
• Not amenable to surgery

• Documented progressive disease within the past 6 months, as defined by 1 of the following criteria:

  • At least 25% increase in radiologically or clinically measurable disease
  • Appearance of new lesions
  • Deterioration in clinical status
• Must have tumor lesions accessible for biopsy
• No known brain metastases

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• ECOG 0-2 OR
• Karnofsky 60-100%

Life expectancy

• More than 3 months

Hematopoietic

• WBC ≥ 3,000/mm^3
• Absolute neutrophil count ≥ 1,500/mm^3
• Platelet count ≥ 100,000/mm^3

Hepatic

• Bilirubin ≤ 1.25 times upper limit of normal (ULN)
• AST and ALT ≤ 3 times ULN (< 5 times ULN if liver metastases are present)

Renal

• Creatinine ≤ 1.5 times ULN OR
• Creatinine clearance ≥ 60 mL/min

Cardiovascular

• No symptomatic congestive heart failure
• No unstable angina pectoris
• No cardiac arrhythmia

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• No active or ongoing infection
• No history of allergic reaction attributed to compounds of similar chemical or biological composition to CCI-779
• No psychiatric illness or social situation that would preclude study compliance
• No other uncontrolled illness
• No other malignancy within the past 3 years except curatively treated nonmelanoma skin cancer or carcinoma in situ of the cervix

PRIOR CONCURRENT THERAPY:

Biologic therapy

• No concurrent prophylactic hematopoietic colony-stimulating factors

Chemotherapy

• More than 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin) and recovered

Endocrine therapy

• Concurrent chronic somatostatin analogues for symptom control allowed provided treatment was initiated > 3 months before study entry

Radiotherapy

• More than 4 weeks since prior radiotherapy, including radioactive octreotide, and recovered

Surgery

• More than 6 weeks since prior surgery

Other

• More than 6 weeks since prior local therapy (e.g., chemoembolization or bland embolization)
• More than 4 weeks since prior investigational agents
• No concurrent combination antiretroviral therapy for HIV-positive patients
• No other concurrent anticancer therapy
• No other concurrent investigational agents