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.