L-folinic acid and 5-fluorouracil in the treatment of advanced breast cancer: A phase II study

Abstract

The combination of 5-fluorouracil (5-FU) and folinic acid (FA) is an active combination for the treatment of advanced breast cancer (ABC). Theoretically, the biologically active isomer of FA, 1-FA, should be more effective than racemic FA in modulating 5-FU activity. Thirty-three patients (pts) with ABC, all previously treated with an anthracycline-based combination for advanced disease were treated with 1-FA: 100 mg/m2 i.v. and 5-FU: 370 mg/m2 i.v. for 5 consecutive days every 4 weeks. Three complete remission (CR) and 11 partial remission (PR) were obtained for an overall response rate of 42% (95% CI = 25-59). Median duration of response was 10 months, median survival was 15 months for responders, 11 months for NC and 3 for PD. Eleven pts experienced a WHO grade III-IV oral mucositis (33%), 6 pts had grade III and one grade IV diarrhea, two pts had grade IV neutropenia resulting in one toxic death. In this heavily pretreated population of pts with ABC, this regimen showed an interesting activity with substantial toxicity. Both the response rate and the pattern of side-effects seem similar to those experienced with the racemic mixture of d,1-FA. Modulated 5-FU warrants an increasing consideration in the treatment of breast cancer.