Inclusion Criteria

DISEASE CHARACTERISTICS:

- Histologically or cytologically confirmed gastric cancer

- Locally advanced, unresectable, or metastatic disease

- Measurable disease, defined as at least 1 lesion that can be accurately measured in ≥
1 dimension as ≥ 20 mm with conventional techniques or as ≥ 10 mm with spiral CT scan

- No known brain metastases

PATIENT CHARACTERISTICS:

- ECOG performance status (PS) 0-2 or Karnofsky PS 60-100%

- WBC ≥ 3,000/mm³

- Absolute neutrophil count ≥ 1,500/mm³

- Platelet count ≥ 100,000/mm³

- Bilirubin normal

- AST/ALT ≤ 2.5 times upper limit of normal

- Creatinine ≤ 1.5 mg/dL

- Not pregnant or nursing

- Negative pregnancy test

- Fertile patients must use effective contraception during study and for 6 months after
completion of study treatment

- Able to swallow

- No history of allergic reactions attributed to compounds of similar chemical or
biologic composition to fluoropyrimidines or platinum chemotherapy agents

- No uncontrolled intercurrent illness including, but not limited to the following:

- Ongoing or active infection

- Symptomatic congestive heart failure

- Unstable angina pectoris

- Cardiac arrhythmia

- Psychiatric illness or social situations that would preclude study compliance

PRIOR CONCURRENT THERAPY:

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

- At least 6 months since prior radiotherapy with capecitabine as a radioenhancer

- No concurrent combination antiretroviral therapy for HIV-positive patients

- No other concurrent chemotherapy

- No concurrent palliative radiotherapy

- No concurrent hormonal therapy except for the following:

- Steroids for adrenal failure

- Hormones for nondisease related conditions (e.g., insulin for diabetes)

- Intermittent use of dexamethasone as an antiemetic

- No other concurrent investigational agents

- No other concurrent anticancer agents or therapies