The prolonged clinical benefit with metronomic chemotherapy (VEX regimen) in metastatic breast cancer patients

Objective: Metronomic chemotherapy is a treatment option for metastatic breast cancer (MBC) patients who require prolonged disease control without cumulative toxicity. Data available on the efficacy and tolerability of prolonged usage of metronomic therapy are limited. Methods: We analyzed patients with MBC, enrolled in a clinical trial, who obtained a prolonged clinical benefit for a duration of at least 12 months with vinorelbine 30 or 40 mg orally three times a week, cyclophosphamide 50 mg daily and capecitabine 500 mg three times a day (VEX regimen). The patients were treated at the European Institute of Oncology, Milan. Results: We identified 67 MBC patients. The median age before starting the VEX regimen was 53 years. There were 59 patients (88%) who had hormone-receptors positive and HER2 negative BC. We had 37 patients who received VEX as the first-line treatment for MBC, while 30 patients were pretreated. The objective response rate was 49% (95% CI, 37-62). The median duration of VEX treatment after the first year was 14 months (min-max range 0.3-81.3 months). The progression-free survival at 3 years was 25.4% (95% CI, 15.7-36.2) and at 4 years was 18.5% (95% CI, 10.1-28.8 time 0 corresponds to 1 year after starting VEX). A total of 25 patients required a dose reduction, 7% of patients experienced G3 hand and foot syndrome. Conclusions: Metronomic VEX regimen can induce prolonged clinical benefit in MBC. On the basis of this long-term safety evaluation, there is no evidence of specific cumulative or delayed toxicities with metronomic chemotherapy.