Albumin-Bound Paclitaxel in the Treatment of Metastatic Breast Cancer

Abstract: The taxanes, paclitaxel and docetaxel, are an important class of antineoplastic agents with relevant clinical activity in both early and advanced breast cancer. Nanoparticle albumin-bound paclitaxel (Abraxane®) is a 130–nm particle cremophor-free formulation of paclitaxel. Exploiting endogenous albumin pathways and avoiding solvent-based toxicities, nab-paclitaxel allows higher intratumor concentrations of paclitaxel through gp60 mediated endothelial transcytosis. Also, because it is free solvents, nab-paclitaxel offers shorter infusions and easily administration with no premedication and special infusions sets. In a phase III randomized trial, nab-paclitaxel at 260 mg/m2 every 3 weeks seems to have a superior therapeutic index than Cr-El pacli-taxel, with a higher response rate and longer time to progression and with less toxicity, except peripheral neuropathy. Based on these results, nab-paclitaxel was approved for the treatment of metastatic breast cancer in patients who have failed first-line treatment for metastatic disease and for whom standard; anthracycline containing therapy is not indicated. The results of the comparison of three doses of nab-paclitaxel with docetaxel in a randomized phase II trial suggest a superior efficacy and safety of weekly nab-paclitaxel compared with 3-weekly docetaxel. All the available data suggest the superior therapeutic index of nab-paclitaxel compared with both docetaxel and Cr-EL paclitaxel. Weekly nab-paclitaxel may be an adequate alternative to classic formulations of taxanes in the treatment of patients with metastatic breast cancer