Background: Few overlapping toxicities and oral formulations make capecitabine plus oral vinorelbine an attractive new combination for treating patients with breast cancer. An all-oral regimen minimizes inconvenience for the patient and saves medical resources.
Patients and methods: To determine the recommended dose for this all-oral combination, we conducted a phase I study in 21 patients with metastatic breast cancer after failure of previous chemotherapy with anthracylines and/or taxanes for advanced disease. Capecitabine 1000 mg/m2 twice daily was given on days 2-7 and 9-14. Vinorelbine was administered at escalating doses of 40-80 mg/m2 on days 1 and 8 every 3 weeks. Dose escalation of vinorelbine was performed in cohorts of 3 patients, but the dose of vinorelbine could also be increased to the next level in the same patient after 3 cycles if there were no dose-limiting toxicities. In total, 173 cycles were administered (median, 8 cycles; range 1-21+ cycles).
Results: Treatment was well tolerated: there were no grade 4 toxicities, and the only grade 3 toxicities in > 1 cycle were hand-foot syndrome and neutropenia (2% of cycles each). The maximum tolerated dose could not be determined using predefined criteria. However, in this heavily pretreated patient population, intrapatient vinorelbine dose escalation > 60 mg/m2 was rarely achieved. Thus, we considered vinorelbine 60 mg/m2 to offer the best dose level-toxicity ratio. At this dose, grade 3 toxicities occurred in only 7% of the 58 cycles administered. Among 19 evaluable patients, 7 exhibited response or stable disease lasting > 6 months, giving a clinical benefit rate of 37%. Duration of response in the 2 responding patients was 5 months and > 16 months.
Conclusion: The all-oral combination of capecitabine/vinorelbine is well tolerated and active in heavily pretreated patients. Oral vinorelbine 60 mg/m2 is recommended in combination with capecitabine 1000 mg/m2 twice daily for further evaluation.