Phase II trial of an all‐oral regimen of tegafur and folinic acid in patients with previously treated metastatic breast cancer

Background. Tegafur is an antimetabolite slowly metabolized to 5-fluorouracil in vivo. Protracted administration of oral tegafur is active in metastatic breast cancer, with reported response rates ranging from 29 to 44%. The addition of folinic acid could improve the efficacy of tegafur by means of biochemical modulation. Methods. A prospective Phase II trial in patients with pretreated metastatic breast cancer was performed. The regimen consisted of oral tegafur (750 mg/m2/day) and oral folinic acid (45 mg/day) for 21 days, recycling at day 28. Results. Twenty-five patients were included. Eight partial responses were observed for an objective response rate of 32% (95% confidence intervals for response, 23-41%). The median duration of response was 7 months. According to WHO criteria, 24% of patients experienced grade 3 mucositis and 12% grade 3 diarrhea, but no other significant toxicities were observed. Twenty-eight percent of patients required dose reductions for toxicity. Conclusions. A significant response rate with oral tegafur and folinic acid in patients with heavily pretreated breast cancer was found. This all-oral regimen, which could be safely administered on an outpatient basis, deserves further evaluation to define the role of folinic acid on the activity of tegafur in metastatic breast cancer. Cancer 1995; 75:831-5.