A phase I study of vinflunine in combination with capecitabine in patients with metastatic breast cancer previously treated with anthracyclines and taxanes.

Purpose: A phase I study was performed to determine the maximal tolerated dose (MTD), recommended dose (RD), safety and efficacy of vinflunine when combined with capecitabine in patients with metastatic breast cancer (MBC) previously treated with anthracyclines and taxanes, with pharmacokinetic blood sampling to test potential drug-drug interactions.
Patients and Methods: Sixteen patients with MBC who had received anthracyclines and taxanes in the neo/adjuvant setting, if progression occurred during or within 12 months of chemotherapy completion, and/or as first-line chemotherapy of MBC were enrolled. Vinflunine (VFL) was given on day 1 with capecitabine (CAPE) twice daily from days 1 to 14, every 3 weeks. Three dose levels (DL) were investigated (DL1: VFL 280 mg/m² and CAPE 1,650 mg/m²/day, DL2: VFL 320 mg/m² and CAPE 1,650 mg/m²/day and DL3: VFL 280 mg/m² and CAPE 2,000 mg/m²/day).
Results: The RD was established as vinflunine 280 mg/m² on day 1 plus capecitabine 1,650 mg/m²/day on days 1 to 14 given every 3 weeks. Dose-limiting toxicities were grade 4 neutropenia lasting at least 7 days for 2 patients, anorexia with fatigue for 1 patient and diarrhoea with fatigue, anorexia and febrile neutropenia for 1 patient. Neutropenia was the main toxicity of the combination, it was reported in 15 patients (93.8%) with grade 3 in 7 patients (43.8%) and 22.6% of cycles and grade 4 in 7 patients (43.8%) and 19.8% of cycles. Complications were rare with only one patient experiencing febrile neutropenia at DL exceeding the RD. The most frequent non-haematological toxicities were fatigue and gastrointestinal disorders; however, no grade 3 or 4 episode was observed at the RD. Hand-foot syndrome was reported in 5 patients (31.3%) and 22.6% of cycles, no episode of grade 3 was seen. Concerning pharmacokinetics, no modifications were detected for VFL, while slight accumulation between days 1 and 14 was observed for 5-FU formed from CAPE. The risk of clinical significant drug-drug interaction was considered weak. Objective partial responses were reported in 7 patients, yielding a response rate of 43.8% in the all-treated population according to the investigator assessment.
Conclusions: The combination of vinflunine and capecitabine is safe and showed promising antitumour activity in MBC patients who have failed prior anthracyclines and taxanes. Further clinical development of this combination is warranted.