nab-Paclitaxel versus Docetaxel for the First-line Treatment of Metastatic Breast Cancer

Taxane-based treatment regimens are standard first-line therapies for metastatic breast cancer (MBC). The clinical benefit of solvent-based taxanes, including solvent-based paclitaxel and docetaxel, in MBC has been established in large randomized clinical trials. Docetaxel has demonstrated greater efficacy versus solvent-based paclitaxel in at least one trial, but both solvent-based paclitaxel and docetaxel are associated with undesirable dose-limiting toxicities, including neutropenia, sensory neuropathy, and hypersensitivity reactions. nab-Paclitaxel, an albuminbound form of paclitaxel, was developed to improve the therapeutic index of taxane treatment. This review summarizes preclinical experiments and clinical data from MBC trials comparing nab-paclitaxel with docetaxel. In preclinical studies, nab-paclitaxel more effectively suppressed tumor growth than docetaxel (80 versus 29 % inhibition) in breast cancer tumor xenograft models and was associated with less toxicity. Clinical studies confirmed these findings and reported a better therapeutic index with nab-paclitaxel than docetaxel. As such, the clinical experience with nabpaclitaxel supports its role as an important advance in the treatment of MBC with taxane-based regimens.