Clinical Outcomes of Women with Metastatic Breast Cancer Treated with Nab-Paclitaxel: Experience from a Single Academic Cancer Centre

Background: Nab-paclitaxel is a solvent-free, taxane-based chemotherapy approved for the treatment of metastatic breast cancer (mbc). This study reports clinical benefit and toxicities experienced by women with mbc treated with nab-paclitaxel at the Ottawa Hospital Cancer Centre. Methods: Women with mbc treated with single-agent nab-paclitaxel between June 2006 and December 2010 were included in this analysis. Retrospective data obtained included demographics, disease characteristics, prior chemotherapy, nab-paclitaxel treatment, toxicity, and survival. Clinical benefit was defined as partial or complete response or stable disease (by clinical or radiologic evaluation, or both) at 6 months or more. Results: Of 43 women (mean age: 57.0 years; range: 34–74 years), most had disease positive for estrogen or progesterone receptor (72.1%, 58.1%), or both. Nab-paclitaxel was administered weekly (qw: 44.2%), every 3 weeks (q3w: 46.5%), q3w switched to qw (7.0%), or qw switched to q3w (2.3%). Median duration of therapy was 5.1 months (qw) and 3.0 months (q3w). Sensory neuropathy was the primary toxicity (45.4% qw, 38.1% q3w; p = 0.62). Clinical benefit was observed in most women (76.2% qw, 57.1% q3w; p = 0.20). Women receiving nab-paclitaxel had a median overall survival of 13.6 months qw (range: 8.1–28.3 months) and 10.8 months q3w (range: 5.9–17.9 months; p = 0.03). Regardless of dosing schedule, women experiencing clinical benefit lived significantly longer than those not experiencing a benefit (17.3 months vs. 7.7 months; hazard ratio: 0.14; 95% confidence interval: 0.06 to 0.33). Conclusions: Our clinical experience demonstrates that most women treated with nab-paclitaxel experienced some clinical benefit. Patients achieving clinical benefit lived significantly longer than those who did not. Nab-paclitaxel was well tolerated, with the primary toxicity being mild sensory neuropathy. Nab-paclitaxel represents another treatment option, with a favourable toxicity profile, for women with mbc.