DISEASE CHARACTERISTICS:

• Histologically confirmed advanced solid tumor

  • Metastatic or unresectable disease
  • Standard curative or palliative measures do not exist or are no longer effective
• 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
• Hemoglobin ≥ 8 g/dL
• Absolute neutrophil count ≥ 1,500/mm^3
• Platelet count ≥ 100,000/mm^3

Hepatic

• Bilirubin normal
• AST and ALT ≤ 2.5 times upper limit of normal
• No unstable or uncompensated hepatic disease

Renal

• Creatinine normal OR
• Creatinine clearance ≥ 60 mL/min
• No prior hypercalcemia
• No kidney, ureteral, or bladder stones within the past 10 years
• No unstable or uncompensated renal disease

Cardiovascular

• Ejection fraction ≥ 30%
• No heart failure or significant heart disease
• No significant arrhythmias
• No myocardial infarction within the past 3 months
• No unstable angina pectoris
• No symptomatic congestive heart failure
• No other unstable or uncompensated cardiac disease

Pulmonary

• No evidence of clinically active interstitial lung disease

  • Chronic, stable, asymptomatic, radiographic changes allowed
• No other unstable or uncompensated respiratory disease

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception during and for 30 days after study treatment
• Able to receive oral medication
• Willing to have serial skin biopsies
• No prior allergic reaction to compounds of similar chemical or biological composition to study drugs or other agents used in this study
• No ongoing or active infection
• No known severe hypersensitivity to gefitinib or any of its excipients
• No psychiatric illness or social situation that would preclude study compliance
• No other severe or uncontrolled systemic disease or concurrent illness that would preclude study participation
• No other significant clinical disorder or laboratory finding that would preclude study participation

PRIOR CONCURRENT THERAPY:

Biologic therapy

• No concurrent filgrastim (G-CSF) or sargramostim (GM-CSF)

Chemotherapy

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

Endocrine therapy

• No other concurrent systemic glucocorticoid therapy

Radiotherapy

• More than 4 weeks since prior radiotherapy and recovered

Surgery

• Recovered from prior major surgery
• No prior nephrectomy

Other

• Recovered from all prior anticancer therapy
• More than 30 days since prior non-approved or investigational drugs
• More than 7 days since prior thiazides

• No concurrent administration of any of the following:

  • Combination antiretroviral therapy for HIV-positive patients
  • Phenytoin
  • Carbamazepine
  • Barbiturates
  • Rifampin
  • Phenobarbital
  • Hypericum perforatum (St. John's wort)
  • Calcium supplements
  • Thiazides
  • Digoxin
• No other concurrent investigational or commercial anticancer agents or therapies