Paclitaxel is a mitotic inhibitor used in cancer chemotherapy. It was discovered in a U.S. National Cancer Institute program at the Research Triangle Institute in 1967 when Monroe E. Wall and Mansukh C. Wani isolated it from the bark of the Pacific yew tree, Taxus brevifolia and named it taxol. When it was developed commercially by Bristol-Myers Squibb (BMS) the generic name was changed to paclitaxel and the BMS compound is sold under the trademark TAXOL. In this formulation, paclitaxel is dissolved in Cremophor EL and ethanol, as a delivery agent. A newer formulation, in which paclitaxel is bound to albumin, is sold under the trademark Abraxane.
Paclitaxel is now used to treat patients with lung, ovarian, breast cancer, head and neck cancer, and advanced forms of Kaposi's sarcoma. Paclitaxel is also used for the prevention of restenosis.
Paclitaxel stabilizes microtubules and as a result, interferes with the normal breakdown of microtubules during cell division. Together with docetaxel, it forms the drug category of the taxanes. It was the subject of a notable total synthesis by Robert A. Holton.
While offering substantial improvement in patient care, paclitaxel has been a relatively controversial drug. There was originally concern because of the environmental impact of its original sourcing, no longer used, from the Pacific yew. In addition, the assignment of rights, and even the name itself, to Bristol-Myers Squibb were the subject of public debate and Congressional hearings.