Adenocarcinomas of the small bowel and ampulla of Vater represent rare cancers that have limited data regarding first-line therapy. We conducted a phase II trial to evaluate the benefit of capecitabine in combination with oxaliplatin (CAPOX) in patients with advanced adenocarcinoma of small bowel or ampullary origin.

Eligible patients with metastatic or unresectable tumors and no prior systemic chemotherapy for advanced disease participated in this phase II trial. CAPOX was administered as a 21-day cycle with oxaliplatin 130 mg/m(2) on day 1 and capecitabine 750 mg/m(2) twice a day on days 1 through 14. The primary end point was overall response rate as assessed by Response Evaluation Criteria in Solid Tumors.

Thirty-one patients were enrolled onto the study, and 30 patients received study treatment. The confirmed overall response rate was 50%; three patients with metastatic disease achieved complete responses. The median time to progression (TTP) was 11.3 months, and the median overall survival (OS) was 20.4 months. Subset analysis of patients with metastatic disease only (n = 25) revealed a median TTP of 9.4 months and median OS of 15.5 months. The most common grades 3 or 4 toxicities included fatigue (30%), peripheral neuropathy (10%), vomiting (10%), diarrhea (10%), and neutropenia (10%).

When administered to patients with good performance status, CAPOX is well tolerated and produces a superior response rate and longer OS compared with other regimens in the literature. CAPOX should be considered a new standard regimen for advanced small bowel and ampullary adenocarcinomas.