China and U.S. Seek to Protect Cancer-Fighting Tree
NEW YORK The United States and China want to expand trade regulations to protect Asian yew trees, a plant that provides the compound for one of the world's top-selling chemotherapy drugs but is threatened by poaching.
Chinese herbalists have used trees of the taxus species, also known as yew trees, for centuries to treat common ailments.
In the late 1960s, scientists in North Carolina found that extract of yew bark fought tumors, and in the early 1990s, the U.S. government approved the use of paclitaxel, also known as taxol, by drug company Bristol-Myers Squibb for chemotherapy.
Taxol, whose patent expired in the United States in 2001, is one of the best-selling drugs for treating lung, ovarian, and breast cancers. In 2003, drug companies sold more than $4 billion of products with taxol and other drugs derived from yew trees known as taxanes.
Yews grow in Asia, Europe, and North America, but in some regions of China they have been ravaged by peasants who illegally fell them to sell the bark to the international pharmaceutical trade, said Pat Ford, a botanist at the U.S. Fish and Wildlife Service in Washington, and member of CITES, a U.N. body formerly known as the Convention on International Trade in Endangered Species.
Some Chinese companies are also suspected of using a traditional method to extract taxol that involves the wasteful cutting down of 3,000 trees to make less than half a pound of taxol, CITES said.
China and the United States have proposed adding four types of Asian yew trees to the Appendix II listings at the Oct. 2-14 CITES meeting in Bangkok, according to CITES.
Under Appendix II, trade in species "must be controlled in order to avoid utilization incompatible with their survival," according to CITES regulations. CITES placed one yew tree on Appendix II in 1995 following a proposal by India.
"We are trying to make sure that those species remain viable in the wild, and the only way we see that we could possibly accomplish that is under the CITES listing," said Ford.
"The total current population of the various taxus species is not very well known, but it is known that there is ongoing destruction of the forests in China," said Simon Habel, an endangered species expert at the World Wildlife Fund in Washington. "By having this on Appendix II, we'll have a much better idea of the volume of trade, which at the moment to try to get accurate information out of drug companies and other companies is rather difficult."
Bristol-Myers Squibb says it would not be affected by the trade regulations because it harvests its own supplies rather than taking trees from the wild. The company has obtained its paclitaxel since 1995 through semi-synthetic methods and by harvesting only the needles of the trees without cutting them down.
"The process is sufficient for providing the needs of the patient, we can meet demand, and still be protective of it (yew trees) in the process," Bristol Myers Squibb spokesman Wilson Grabill said in a telephone interview.