Study For Patients With Untreated Gastric Cancer Who Will Receive Capecitabine And Lapatinib

An Exploratory, Phase II Trial to Determine the Association of Lapatinib Induced Fluoropyrimidine Gene Changes With Efficacy Parameters of Lapatinib and Capecitabine in First Line Gastric Cancer

The study will determine if changes in expression of markers involved in the 5-FU pathways are associated with response to treatment with the combination of lapatinib and capecitabine independent of tumor erbB2 status.

Inclusion Criteria:

• Has signed inform consent
• Untreated, newly diagnosed, advanced metastatic or unresectable gastric cancer, including the gastro-esophageal junction
• Tumor accessible to and patient consent for endoscopic biopsy at study start and after 7 days of single agent Lapatinib
• Measurable disease according to RECIST criteria
• Male or female > or = 18 years of age
• Cardiac ejection fraction within the institutional range of normal as measured by echocardiogram
• must have adequate organ function as defined by baseline laboratory values

Exclusion Criteria:

• Gastric carcinoid, sarcomas, or squamous cell cancer
• Pregnant or lactating females
• Intractable nausea, vomiting, or gastro intestinal obstruction requiring decompression and drainage with a gastric tube or nasogastric suction.
• patients who require continuous enteral feeding
• Malabsorption syndrome or uncontrolled inflammatory GI disease (Crohn's or ulcerative colitis
• Known history of uncontrolled or symptomatic angina, arrhythmias, or congestive heart failure