Long term disease control in taxane-refractory metastatic breast cancer treated with nab paclitaxel

543 Background: nanoparticle albumin bound (nab) paclitaxel (ABI-007, Abraxane, ABX) is a novel, cremophor-free paclitaxel preparation with a high therapeutic index that does not require pre-medication. Methods: We have conducted a Phase II study of weekly ABX in patients with taxane-refractory, measurable metastatic breast cancer (MBC). Patients received ABX 100mg/m2 weekly over 30 minutes on day 1, 8, and 15 on a 28-day cycle without pre-medication. Results: 106 patients have been enrolled and 66 patients are currently evaluable for toxicity and response. Patients were considered taxane-refractory if they had progressive MBC while receiving paclitaxel, docetaxel or both (59 patients); or if they had relapsed within 12 months of adjuvant taxane (7 patients). Median age was 53 (range, 34–75); median number of metastatic sites was 3 (range, 1–6); 31 (47%) patients have hormone receptor positive MBC; median number of prior chemotherapy regimens (metastatic setting) was 3 (range, 1–10). Thirty-five (53%) pat...