Phase II trial of gemcitabine plus UFT as salvage treatment in oxaliplatin, irinotecan and fluoropyrimidine-refractory metastatic colorectal cancer
INTRODUCTION Fluoropyrimidines with oxaliplatin or irinotecan plus bevacizumab is the standard chemotherapy combination in patients with advanced colorectal cancer (CRC). Gemcitabine acts synergistically with fluoropyrimidines to enhance the binding of thymidylate synthase and increase inhibition of DNA synthesis. The objective of this review is to evaluate the literature for evidence of efficacy and safety of fluoropyrimidine plus gemcitabine (FG) in patients with advanced CRC. METHODS Relevant studies were identified in PubMed, Ovid, Cochrane database and the American Society of Clinical Oncology abstracts using the following search terms: gemcitabine, fluorouracil, capecitabine and colorectal cancer. Only studies using the FG combination were selected. RESULTS Forty-two advanced CRC patients were evaluated in two Phase I studies and the maximum tolerated dose of gemcitabine was 900 - 1,000 mg/m(2) weekly with either bolus 5-fluorouracil (5-FU) or capecitabine. A total of 216 advanced CRC patients were evaluated in six Phase II studies. Gemcitabine (750 - 1,250 mg/m2) with either 5-FU (continuous infusion or bolus) or capecitabine was administered as first-line therapy in two studies and as third-line therapy in three studies. The range reported for overall response rate was 30 - 38.3%, median time to progression was 4 - 8.3+ months and median survival was 9.8 - 18+ months. The most commonly reported grade 3 - 4 toxicities were neutropenia, thrombocytopenia and mucositis. CONCLUSIONS Fluoropyrimidine plus gemcitabine is clinically active in patients with refractory CRC demonstrating prolonged median time to progression and acceptable toxicity only when bolus 5-FU was not used. Studies are underway to evaluate the combinations of FG with other chemotherapy or targeted agents. Meanwhile, FG may be considered for patients with advanced CRC who are refractory to primary treatment without other options or who are not eligible for clinical studies.