Taxoids: New Weapons against Cancer; June 1996; Scientific American Magazine; by Nicolaou, Guy, Potier; 5 Page(s)

Just five years ago the chemical known as taxol made headlines as a breakthrough treatment for ovarian cancer. There was only one problem--the drug was incredibly hard to come by. Researchers had to extract the substance from the bark of the Pacific yew (Taxus brevifolia) in a process that inevitably killed the tree. Even more frustrating, yews grow slowly (a fullgrown tree is around 25 feet tall), and each plant yields little bark. A 100-yearold tree provides only a gram of the compound, about half the amount needed for a single treatment. In addition, yews that produce taxol exist within the delicate old-growth forest of the Pacific Northwest, and harvesting the endangered trees would cause irreparable harm to this ecosystem. As the number of Pacific yews dwindled, environmentalists argued to protect the few remaining trees, while cancer patients and their families pleaded for more of the drug.

Today the headlines about taxol are quite different. In 1994 the U.S. Food and Drug Administration approved semisynthetic taxol, made in the laboratory and available in unlimited quantities, for use in the treatment of various cancers. Early this year a team of physicians based at Emory University announced results from an extensive study of the drug. Instead of lamenting its scarcity, the researchers emphasized its unexpected potency. According to the findings, women suffering from advanced ovarian cancer who took taxol in combination with another anticancer medication lived an average of 14 months longer than patients who received other therapies. Taxol is now considered one of the most promising treatments for breast and ovarian cancer. Other studies have demonstrated its effectiveness against lung cancer and melanoma. How did taxol, an agent initially known mainly for its absence, become renowned for its powerful presence?