Two
taxanes,
paclitaxel and
docetaxel, are among the most widely used chemotherapeutic agents in solid
tumor oncology, with efficacy against
tumors of the breast, lung, head and neck, ovary, prostate, stomach and urothelium. The
taxanes have been studied extensively and have been proven effective for treating early and advanced
breast cancer. However,
paclitaxel and
docetaxel are both highly hydrophobic compounds, requiring synthetic
solvents for parenteral administration. The
solvents in commercially available preparations cause life-threatening toxic effects and decreased efficacy, and they are inconvenient to administer. Nanoparticle
albumin-bound paclitaxel (nabP) is a novel,
solvent-free formulation of
paclitaxel. With nabP, in contrast to standard
paclitaxel, life-threatening
hypersensitivity reactions have not been observed, and it can be administered safely without
steroid and
antihistamine premedication. Furthermore, nabP exploits cellular and
tumor transport mechanisms to preferentially target
tumor cells. Data from phase III studies of metastatic
breast cancer demonstrated higher response rates, longer time to progression and an improved toxicity profile for nabP compared with standard
paclitaxel. The U.S. Food and Drug Administration approved nabP in late 2004 for treatment of metastatic
breast cancer after failure of an
anthracycline-based regimen.