Phase II trial of ixabepilone in patients with metastatic breast cancer (MBC) who are resistant to an anthracycline, a taxane and capecitabine

• Published in: Journal of clinical oncology Vol. 24; no. 18_suppl; p. 660
• Main Authors: Thomas, E., Perez, E. A., Mukhopadhyay, P., Lerzo, G., Pivot, X., Bosserman, L. D., Mullaney, B., Vahdat, L., Hortobagyi, G. N.
• Format: Journal Article
• Language: English
• Published: 20.06.2006
• ISSN: 0732-183X; 1527-7755
• DOI: 10.1200/jco.2006.24.18_suppl.660

Abstract only 660 Background: Patients (pts) with MBC previously treated with an anthracycline, a taxane and capecitabine have very limited treatment options. Ixabepilone is the first semi-synthetic analog in a new class of cytotoxic agents, the epothilones. It has shown activity in breast and other tumors. Methods: This single-arm Phase II trial was designed to assess the objective response rate (ORR) of ixabepilone in MBC pts resistant to an anthracycline, a taxane and capecitabine. Pts had to be resistant to each regimen as defined by progression within 8 wks in the metastatic setting or recurrence within 6 months (mo) of adjuvant anthracycline/taxane. Capecitabine must have been given in the metastatic setting. Response was assessed by an independent radiology review committee (IRRC; primary analysis) and by each investigator per RECIST. Ixabepilone was administered IV at 40 mg/m 2 over 3 h every 3 wks. Results: A total of 126 pts were treated: median age 51 yrs (range 30–78), Karnofsky PS range 70–100% and 70% pts had baseline liver metastases. 88% pts had received ≥2 prior metastatic regimens. 113 pts were response evaluable (had target disease by IRRC and met eligibility criteria for prior therapy). Median duration of response was 5.3 mo. Stable disease (SD) was the best response in 50% pts and 14% pts had SD ≥6 mo duration. Median PFS was 3.1 mo. Pts received a median of 4 cycles (range 1–16). The most common Grade 3/4 treatment-related adverse events were sensory peripheral neuropathy (14%), fatigue (10%), myalgia (7%), and stomatitis (6%). The neuropathy was cumulative and reversible. Time to resolution (to Grade 1 or baseline) for Grade 3/4 neuropathy was 5.4 wks by Kaplan-Meier analysis. Grade 3/4 neutropenia and thrombocytopenia occurred in 54% and 7% of pts, respectively. Febrile neutropenia was reported in 3% pts. Conclusions: Ixabepilone demonstrates promising clinical activity and a manageable safety profile in patients highly resistant to standard chemotherapy. [Table: see text] [Table: see text]