A phase I study of capecitabine in combination with vinorelbine in advanced breast cancer

A phase I study was conducted in order to determine the maximum tolerated dose (MTD) and dose-limiting toxicities (DLTs) of the combination of vinorelbine and capecitabine in patients affected with metastatic breast cancer. Eighteen patients with histologically confirmed advanced breast cancer, who had failed =1 prior chemotherapy regimen, were enrolled. The median age was 56 years (range, 39-70 years). All but 1 had previously received a combination of anthracyclines and taxanes; performance status (Eastern Cooperative Oncology Group) was 0/1 or 2 in 13 and 5 patients, respectively. Vinorelbine was administered at a fixed dosage of 25 mg/m2 on days 1 and 8 every 3 weeks. Capecitabine was administered orally, at an escalated dose ranging from 1400 mg/m2 to 2250 mg/m2 for 14 consecutive days starting on day 1 of the cycle, divided into 2 daily doses delivered half an hour after eating at 12-hour intervals. Three patients were treated at each dose level: if 1 patient developed a DLT, an additional 3 patients were treated at the same dose level. If 2 additional patients experienced DLT, no further escalation was allowed and the previous dose level was declared MTD. Dose-limiting toxicity was reached at 2250 mg/m2 of capecitabine with 3 out of 3 patients experiencing grade 4 neutropenia plus grade 3 diarrhea and grade 3 oral mucositis in 1 patient). Thus, MTD was defined at 2000 mg/m2 capecitabine. Other observed grade 2 side effects were: 1 patient with neutropenia, 1 with hand-foot syndrome, 2 with mucositis, 1 with cutaneous rash, and 1 with thrombocytopenia. With regard to response rate, we observed 1 complete response (5.5%), 6 partial responses (33%), and 4 disease stabilizations (22%). The median time to progression was 12 weeks and the median survival 41 weeks. The MTD of capecitabine in combination with vinorelbine at 25 mg/m2 dosage on days 1 and 8 of a 3-week schedule is 2000 mg/m2/day for 14 consecutive days. Moreover, this regimen showed interesting activity with 61% overall disease control (complete plus partial response plus disease stabilization) in patients pretreated with anthracyclines and taxanes warranting further investigations in a large, multicenter phase II study.