Erlotinib Combined With Gemcitabine in Treating Patients With Newly Diagnosed Locally Advanced or Metastatic Pancreatic Cancer or Other Solid Tumors

DISEASE CHARACTERISTICS:

* Histologically or cytologically confirmed locally advanced or metastatic epithelial carcinoma of the pancreas or other malignancy considered to be potentially responsive to gemcitabine

  * Newly diagnosed or gemcitabine naive
* Measurable or evaluable disease
* Not amenable to surgical intervention due to medical contraindications or non-resectability of the tumor
* No islet cell tumors or other non-epithelial cell carcinomas of the pancreas
* No active CNS metastases or leptomeningeal disease

  * Treated or asymptomatic brain metastases are allowed if on a stable dose of corticosteroids and/or there is no change in brain disease status for at least 4 weeks after related therapy (e.g., whole-brain radiotherapy)

PATIENT CHARACTERISTICS:

Age:

* 18 and over

Performance status:

* Karnofsky 70-100%

Life expectancy:

* Not specified

Hematopoietic:

* Absolute neutrophil count at least 1,500/mm\^3
* Platelet count at least 100,000/mm\^3

Hepatic:

* Bilirubin no greater than 2.0 mg/dL (except for documented Gilbert's syndrome)
* AST or ALT less than 2 times upper limit of normal (ULN) (no greater than 5 times ULN if hepatic obstruction or metastases present)
* Albumin at least 2.5 g/dL

Renal:

* Creatinine less than 1.5 times ULN OR
* Creatinine clearance at least 60 mL/min

Cardiovascular:

* No significant cardiovascular disease
* No history of congestive heart failure currently requiring therapy
* No ventricular arrhythmia requiring anti-arrhythmic therapy
* No severe conduction disturbances
* No angina pectoris requiring therapy
* No myocardial infarction within the past 6 months

Gastrointestinal:

* No significant gastrointestinal abnormalities including:

  * Requirement for IV alimentation
  * Active peptic ulcer disease

Ophthalmic:

* No significant ophthalmologic abnormalities including:

  * Severe dry eye syndrome
  * Keratoconjunctivitis sicca
  * Sjogren's syndrome
  * Severe exposure keratopathy
  * Disorders that would increase the risk for epithelium-related complications (e.g., bullous keratopathy, aniridia, severe chemical burns, or neutrophilic keratitis)
  * Abnormal Schirmer test (less than 2 mm) allowed provided there is no evidence of clinically significant corneal surface abnormalities

Other:

* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception
* No known or suspected hypersensitivity to gemcitabine
* No uncontrolled infection
* HIV negative
* No other malignancy within the past 5 years except treated non-melanoma skin cancer or carcinoma in situ of the breast or cervix
* No other life-threatening illness
* No psychiatric disorders or altered mental status the would preclude informed consent or study

PRIOR CONCURRENT THERAPY:

Biologic therapy:

* At least 28 days since prior immunotherapy or biological response modified therapy for the primary malignancy
* No concurrent immunotherapy or biologic response modifier therapy for the primary malignancy

Chemotherapy:

* See Disease Characteristics
* At least 28 days since prior chemotherapy for the primary malignancy
* No prior mitomycin or nitrosoureas for the primary malignancy
* No more than 6 prior courses of chemotherapy with an alkylating agent for the primary malignancy
* No prior gemcitabine for the primary malignancy except as a low-dose (less than 500 mg/m\^2) radiosensitizer administered concurrently with or within 2 weeks after radiotherapy at least 3 months ago
* No other concurrent chemotherapy for the primary malignancy

Endocrine therapy:

* See Disease Characteristics
* At least 28 days since prior systemic hormonal therapy (except LH-RH agonists) for the primary malignancy
* No concurrent systemic hormonal therapy (except LH-RH agonists) for the primary malignancy
* Other concurrent endocrine therapy is allowed as follows:

  * Hormonal therapy (e.g., megestrol) for appetite stimulation
  * Nasal, ophthalmic, or topical glucocorticoids
  * Oral glucocorticoids for adrenal insufficiency
  * Low-dose maintenance steroids

Radiotherapy:

* See Disease Characteristics
* At least 28 days since prior radiotherapy for the primary malignancy or metastases and recovered
* No prior wide-field radiotherapy to 25% or more of marrow-bearing bone
* No prior pelvic irradiation
* No concurrent radiotherapy for the primary malignancy or metastases
* No concurrent wide-field radiotherapy for pain management

Surgery:

* See Disease Characteristics
* Recovered from any prior surgery
* No prior surgical procedures affecting absorption

Other:

* No prior agent for the primary malignancy targeting the epidermal growth factor receptor (EGFR) or EGFR-specific tyrosine kinase activity