Nanotech News

February 7, 2005

Abraxane™ Approved To Treat Metastatic Breast Cancer

Albumin nanoparticle increases efficacy, reduces toxicity, of Taxol®

On January 7, 2005, Abraxane, a nanoparticulate formulation of the widely used anticancer drug paclitaxel, received final FDA approval for use in patients with metastatic breast cancer who have failed combination chemotherapy. Abraxane, created and developed by American Bioscience (ABI), based in Schaumburg, IL, is the first approved drug to use nanoparticles made of the protein albumin to improve the therapeutic and safety properties of a drug.

One of the major limitations in using paclitaxel is its poor solubility in blood and other biological fluids. As a result, the drug must be mixed with various toxic solvents, which limits the amount of drug that patients receive. In addition, patients receiving solvent-based paclitaxel must also receive corticosteroids to counteract the toxicity of these solvents.

Albumin, the most plentiful protein in human serum, turns out to be a good natural "solvent" for paclitaxel. Scientists at ABI developed methods for making nanoparticles from the material and loading paclitaxel into these nanoparticles, which allows patients to safely receive 50 percent more paclitaxel per dose. In addition, experimental data suggests that the albumin nanoparticles interact with receptors present on tumor blood vessels that transport the nanoparticles into tumors. This interactivity may account for the increased levels of paclitaxel seen in tumors treated with Abraxane compared to solvent-based paclitaxel.

Clinical trials in 454 patients with metastatic breast cancer showed that Abraxane achieved almost a doubling of tumor response rate compared to that obtained by Taxol, the brand name for paclitaxel. In addition, Abraxane appeared to be better tolerated than Taxol, though Abraxane, like Taxol, does produce a variety of side effects, many severe. Additional clinical trials with Abraxane in other cancers are ongoing.

More information on Abraxane can be found on the FDA website or at ABI's Abraxane website.