DISEASE CHARACTERISTICS:

• Histologically confirmed gastric or gastroesophageal junction (GEJ) adenocarcinoma

  • Metastatic or locally advanced unresectable disease
  • Siewert's class I, II, or III disease for patients with GEJ adenocarcinoma
• Measurable disease
• No known brain metastases

PATIENT CHARACTERISTICS:

Performance status

• ECOG 0-1

Life expectancy

• Not specified

Hematopoietic

• Absolute granulocyte count ≥ 1,500/mm^3
• Platelet count ≥ 100,000/mm^3
• WBC ≥ 3,000/mm^3
• No evidence of bleeding diathesis

Hepatic

• Bilirubin ≤ 2 mg/dL
• AST and ALT ≤ 2.5 times the upper limit of normal (ULN)
• Alkaline phosphatase ≤ 2.5 times ULN

Renal

• Creatinine ≤ 1.5 mg/dL

Cardiovascular

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

Immunologic

• No history of allergic reaction to compounds of similar chemical or biologic composition to sorafenib
• No acute active infection requiring significant clinical intervention

Other

• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• Must be able to take oral medication without crushing, dissolving, or chewing tablets
• No other uncontrolled illness
• No psychiatric illness or addictive disorder that would preclude study compliance
• No other malignancy within the past 5 years except nonmelanoma skin cancer or carcinoma in situ of the cervix

PRIOR CONCURRENT THERAPY:

Biologic therapy

• No prior antiangiogenesis therapy for recurrent or metastatic disease

Chemotherapy

• Prior adjuvant chemotherapy or chemoradiotherapy allowed (with or without fluorouracil) if completed more than 6 months before evidence of recurrent or metastatic disease
• No prior chemotherapy for recurrent or metastatic disease

Radiotherapy

• See Chemotherapy
• No prior radiotherapy for recurrent or metastatic disease

Surgery

• Not specified

Other

• No prior tyrosine kinase inhibitor therapy or signal transduction inhibitor therapy for recurrent or metastatic disease
• No prior investigational agents for recurrent or metastatic disease
• No concurrent combination antiretroviral therapy for HIV-positive patients

• No concurrent cytochrome P450 enzyme-inducing antiepileptic drugs including the following:

  • Phenytoin
  • Carbamazepine
  • Phenobarbital
  • Rifampin
  • Hypericum perforatum (St. John's wort)
• No other concurrent investigational agents