Phase I/II study of capecitabine and vinorelbine in pretreated patients with metastatic breast cancer.

PURPOSE

To define the maximum-tolerated dose (MTD) and to evaluate the dose-limiting toxicities (DLT) of the combination of capecitabine and vinorelbine in patients with metastatic breast cancer who relapse after adjuvant and/or first-line treatment. In addition, we aimed to obtain data on efficacy and safety at the recommended dose.

PATIENTS AND METHODS

Patients with measurable metastatic breast cancer after failure of prior chemotherapy (including anthracyclines and/or taxanes) were eligible. Capecitabine was administered with a fixed dose of 1000 mg/m(2) orally twice daily for 2 weeks followed by 1 week rest. One treatment cycle consisted of 6 weeks of treatment containing two treatment periods of capecitabine. Vinorelbine was given intravenously at escalated doses of 25 mg/m(2) (dose level 1) and 30 mg/m(2) (dose level 2) on days 1 and 8, and 22 and 29.

RESULTS

Thirty-three patients received a total of 91 cycles of capecitabine and vinorelbine. The median number of administered cycles per patient was three (range one to six). Thirty-one patients were evaluable for toxicity. At dose level 2 four out of seven patients experienced DLTs (nausea/vomiting, febrile neutropenia, grade 4 neutropenia, infection and diarrhea); thus, the MTD was defined. In order to confirm the safety and efficacy, dose level 1 was extended to 24 patients. Two patients [8.3%; 95% confidence interval (CI) 1% to 27%] showed DLTs (hospitalization due to febrile neutropenia and prolonged neutropenia). The main toxicity was neutropenia, which was observed at National Cancer Institute Common Toxicity Criteria grade 3 and 4 in 39% of patients. The overall response rate for capecitabine and vinorelbine was 55% (95% CI 36% to 72.7%), including three patients with a complete remission. The median time to disease progression was 8 months (95% CI 4.3-11.7) with an overall survival of 19.2 months (95% CI 11.3-27.1) based on intention-to-treat analysis.

CONCLUSIONS

The combination of capecitabine and vinorelbine can be administered with manageable toxicity and showed significant efficacy for patients with metastatic breast cancer even after failure of a anthracycline- and/or taxane-based therapy.