Docetaxel–ifosfamide combination in patients with HER2-non-overexpressing advanced breast cancer failing prior anthracyclines

Abstract

The feasibility of the docetaxel-ifosfamide combination, as well as the definition of maximum tolerated doses (MTD) in a previous phase I study, led us to continue evaluating the regimen in an extended phase II study in patients with HER2-non-overexpressing, anthracycline pre-treated advanced breast cancer. Patients with histologically confirmed metastatic breast cancer failing prior anthracycline-based chemotherapy were treated with docetaxel 100 mg/m2 over 1 h on day 1 followed by ifosfamide 5 g/m2 divided over days 1 and 2 (2.5 g/m2/day over 1 h), and recycled every 21 days with prophylactic granulocyte-colony stimulating factor (G-CSF) administration from day 3-until a neutrophil count >10,000/microl. Between March 1999 and June 2002, 71 patients with a median age of 55 years (range, 28-72) and performance status (World Health Organization; WHO) of 1 (range, 0-2) were treated; all were assessable for toxicity and 70 patients for response. Clinical response rates (RRs), on an intention-to-treat basis were: 41/71 [58%; 95% CI, 46.5-69.5%]; 7 complete remissions (CRs), 34 partial remissions (PRs), 15 stable disease (SD) and 15 progressive disease (PD). The median response duration was 7.5 months (2-28 months), median time-to-progression (TTP) 6 months (0.1-30 months), and median overall survival (OS) 12 months (0.1-36 months). Grade 3/4 toxicities included; neutropenia in 63% of patients-with 52% developing grade 4 neutropenia (>or=7 days) and in 11% of these febrile neutropenia (FN), while no grade 3/4 thrombocytopenia was observed. Other toxicities included; peripheral neuropathy grade 2 only in 7%, grade 1/2 reversible central nervous system (CNS) toxicity in 11%, no renal toxicity, grade 2 myalgias in 7%, grade 3 diarrhea in 4%, skin/nail toxicity in 11%, and grade 1/2 fluid retention in 28% of patients. The present report has demonstrated encouraging activity of the docetaxel-ifosfamide combination in anthracycline-pretreated, HER2-negative advanced breast cancer. Therefore, future randomized phase III studies versus single-agent docetaxel or currently established combinations of the latter with other agents in this setting with established clinical activity, such as capecitabine or gemcitabine, will be warranted.

Phase II Study of Vinorelbine Plus Ifosfamide in Patients with Taxane-resistant Metastatic Breast Cancer

“…phase I/II studies that have combined ifosfamide with other agents for treating advanced breast cancer patients, such as doxorubicin, (13) paclitaxel (14) and docetaxel (15,16) and these studies have demonstrated the feasibility of considerably high ifosfamide doses as well as the substantial activity of the employed combinations.…”