RATIONALE: Bortezomib may stop the growth of solid tumors by blocking some of the enzymes needed for cell growth and by blocking blood flow to the tumor. Drugs used in chemotherapy, such as gemcitabine, work in different ways to stop the growth of tumor cells, either by killing the cells or by stopping them from dividing. Giving bortezomib together with gemcitabine may kill more tumor cells.

PURPOSE: This phase I trial is studying the side effects and best dose of bortezomib and gemcitabine in treating older patients with advanced solid tumors.

OBJECTIVES:

Primary

• To determine the maximum tolerated dose of weekly bortezomib and gemcitabine in treating elderly patients with advanced solid tumors.

Secondary

• To characterize the quantitative and qualitative toxicities of bortezomib and gemcitabine in these patients.
• To obtain preliminary information about the anti-tumor activity of bortezomib and gemcitabine.
• To characterize gemcitabine and metabolite pharmacokinetics in patients receiving concurrent bortezomib therapy.

OUTLINE: This is a phase I dose escalation study of bortezomib and gemcitabine.

Patients receive gemcitabine IV over 30 minutes followed 1 hour later by bortezomib IV over 3-5 seconds on days 1 and 8. Treatment repeats every 21 days for up to 6 courses in the absence of disease progression or unacceptable toxicity.

Cohorts of 3-6 patients receive escalating doses of gemcitabine and bortezomib until the maximum tolerated dose of the combination is determined.

Blood is collected periodically for pharmacokinetic and pharmacogenetic studies.

After completion of study treatment, patients are followed every 3 months for up to 1 year.

DISEASE CHARACTERISTICS:

• Histologically or cytologically confirmed diagnosis of advanced non-hematologic malignancy, including any of the following:

  • Breast cancer
  • Lung cancer
  • Colon cancer
  • Pancreatic cancer
  • Head and neck cancer
  • Sarcoma

• Must have failed or become intolerant to prior standard therapy and is no longer likely to respond to such therapy (for all diseases except pancreatic cancer)

  • Pancreatic cancer patients may be enrolled with no prior therapy requirements since gemcitabine is the current standard of care 1st line therapy
• Measurable or nonmeasurable disease
• Concurrent enrollment in the University of Minnesota study "Population Pharmacokinetics and Pharmacogenetics of Gemcitabine in Adult Patients with Solid Tumors" (Human Subjects Code 0508M72989) required
• No symptomatic brain metastases

PATIENT CHARACTERISTICS:

• ECOG performance status of 0-1
• Absolute neutrophil count ≥ 1,500/mm³
• Platelet count ≥ 100,000/mm³
• Hemoglobin ≥ 10 g/dL
• Bilirubin ≤ 1.5 times upper limit of normal (ULN)
• Alkaline phosphatase ≤ 3.0 times ULN (5 times ULN if liver has tumor involvement)
• AST and ALT ≤ 3.0 times ULN (5 times ULN if liver has tumor involvement)
• Calculated or measured creatinine clearance > 30 mL/minute
• Fertile patients must use effective contraception during and for 3 months after study participation
• No serious concomitant medical or psychiatric disorders (e.g., active infection or uncontrolled diabetes) that, in the opinion of the investigator, would compromise the safety of the patient or compromise the patient's ability to complete the study
• No myocardial infarction within the past 6 months
• No NYHA Class III or IV heart failure
• No uncontrolled angina
• No severe uncontrolled ventricular arrhythmias
• No electrocardiographic evidence of acute ischemia or active conduction system abnormalities
• No peripheral neuropathy ≥ grade 2
• No known hypersensitivity to bortezomib, boron or mannitol

PRIOR CONCURRENT THERAPY:

• Recovered from all prior therapy
• Prior systemic chemotherapy, immunotherapy, or biological therapy allowed
• At least 3 months since prior bortezomib and/or gemcitabine
• At least 2 weeks since prior systemic therapy
• At least 3 weeks since prior investigational agents (for reasons other than the treatment of cancer)
• At least 2 weeks since prior radiotherapy
• No prior radiotherapy to ≥ 25% of the bone marrow
• No prior radiotherapy to the whole pelvis
• No concurrent filgrastim (G-CSF) or other hematologic support during course 1 of study treatment