This phase II clinical trial was performed in order to evaluate the pharmacokinetics, toxicity and anti-tumor activity of a novel combination of gemcitabine (GEM), 5-fluorouracil (5-FU) and folinic acid (FA) designed on a specific translational basis. Every 4 weeks, 44 patients with various gastroenteric malignancies, 29 of whom had pancreas carcinoma, received a short intravenous (i.v.) infusion of FA (100 mg/m2) and 5-FU (400 mg/m2) on days 1-5, and GEM 1000 mg/m2 on days 1, 8 and 16. Our results suggest that, although this treatment leads to hematological and gastroenteric toxicity, it is very active in patients with pancreatic carcinoma. We therefore believe that an improved version would merit further investigation in larger scale trials.