Nab-Paclitaxel: A Novel Formulation of Taxane for Treatment of Breast Cancer

Breast cancer is the most common type of cancer diagnosed in women. Anthracyclines and taxanes are the most active and widely used chemotherapeutic agents in the treatment of both early-stage and advanced breast cancer. In the past decade, novel formulations of these cytotoxic agents have been developed to improve efficacy and decrease toxicity. nab-paclitaxel is a solvent-free, albumin-bound 130-nm particle form of paclitaxel (Abraxane®, Abraxis Bioscience, CA, USA), which was developed to avoid toxicities associated with the Cremophor vehicle used in solvent-based paclitaxel. In a Phase III study, nab-paclitaxel demonstrated higher response rates, a better safety profile compared with conventional paclitaxel, and improved survival in patients receiving it as second-line therapy. Based on this pivotal trial, nab-paclitaxel is now approved in the USA for treatment of breast cancer after failure of combination chemotherapy for metastatic disease or relapse within 6 months of adjuvant therapy where prior therapy included an anthracycline unless clinically contraindicated. Recently, several Phase II studies have suggested a role for nab-paclitaxel as a single agent and in combination with other agents for first-line treatment of metastatic breast cancer. Studies are ongoing to explore the use of nab-paclitaxel in other solid tumors such as non-small-cell lung cancer, ovarian cancer and malignant melanoma.