Other factors involved with Abraxane

Another factor could be involved. Because albumin, which normally transports nutrients to cells, accumulates in rapidly growing tumors, it's possible that the bundles of Abraxane in their albumin "envelopes" are sent by express delivery directly to cancer cells. "There are signs indicating that albumin receptors in breast cancer and other cancer cells would preferentially pick up these albumin-bound packets."

If so, that may have exciting implications for other chemotherapy drugs used in breast and other cancers, says Claudine Isaacs, MD, director of the Clinical Breast Cancer Program at the Lombardi Comprehensive Cancer Center at Georgetown University Medical Center in Washington, D.C. "This delivery system probably will not be limited to paclitaxel. Theoretically, you could put any number of chemotherapy drugs in these packets, not just paclitaxel." And years of experience with chemotherapy show that delivery matters. "The same drug can have a very different side effect profile, as well as potentially different benefits and response rates, based on how it's delivered."

So far, Abraxane has only been FDA-approved for use in patients with breast cancer that has recurred or metastasized. Still, many drugs that are first approved for use in this stage of the disease later prove to be effective for women with earlier-stage breast cancer.