DISEASE CHARACTERISTICS:

• Histologically confirmed solid malignancy

  • Advanced or metastatic disease

• Meets either of the following criteria:

  • Standard curative or palliative measures do not exist or are no longer effective
  • Has a clinical rationale for gemcitabine hydrochloride-based therapy
• Evaluable disease, measurable on imaging or by informative tumor markers by RECIST criteria
• No ascites requiring active medical management (i.e., paracentesis, peripheral bilateral edema, or hyponatremia [defined as serum sodium value < 134 Meq/L])
• Has tumor amenable to a single tumor biopsy and is willing to undergo a baseline tumor biopsy* NOTE: *Applies to patients in the expanded cohort who are treated at the maximum tolerated dose
• No active CNS metastases

PATIENT CHARACTERISTICS:

• ECOG performance status 0-1
• Life expectancy ≥ 12 weeks
• Granulocyte count ≥ 1,500/mm³
• Platelet count ≥ 100,000/mm³
• Hemoglobin > 9 g/dL
• Serum creatinine ≤ 2.0 times upper limit of normal (ULN) OR creatinine clearance > 50 mL/min
• Total bilirubin ≤ 2.0 times ULN (≤ 1.5 mg/dL in patients with primary liver cancer or hepatic metastases)
• Transaminase levels ≤ 3.0 times ULN (≤ 5 times ULN in patients with primary liver cancer or hepatic metastases)

• No evidence of active heart disease, including any of the following:

  • Myocardial infarction within the past 3 months
  • Symptomatic coronary insufficiency or heart block
  • Uncontrolled congestive heart failure
  • Moderate or severe pulmonary dysfunction
• No active infection
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for 30 days after completion of study therapy
• Willing and able to undergo blood sampling for pharmacokinetic correlative studies in course 1 (patients in the expanded cohort)

PRIOR CONCURRENT THERAPY:

• At least 4 weeks since prior radiotherapy or chemotherapy and recovered

  • No prior radiotherapy administered to > 30% of marrow-bearing bone mass
• More than 3 weeks since prior major surgery and recovered
• Concurrent palliative radiotherapy for pain caused by tumor lesions (e.g., bone metastases) allowed
• Concurrent bisphosphonate therapy allowed according to local policy
• No concurrent prophylactic granulocyte growth factors (i.e., filgrastim [G-CSF], sargramostim [GM-CSF]) during first course of treatment
• No other concurrent investigational drugs
• No concurrent antitumor therapies (e.g., chemotherapy, hormone therapy, gene therapy, biological therapy, radiotherapy) or other immunotherapy