WASHINGTON — A major drug manufacturer will be given access to a rare and promising cancer drug obtained from the bark of Pacific yew trees on federal land in the West, the Department of Agriculture announced Wednesday.
Agriculture Secretary Edward R. Madigan said the USDA will allow Bristol-Myers Squibb Co. to harvest the bark and speed production of taxol, a scarce substance that scientists believe could be among the most important anti-cancer agents discovered in the past decade.
In studies, taxol has proved effective in treating ovarian and breast cancer. Researchers believe that it also may be useful in treating lung and colon cancer.
Wednesday's agreement, however, highlighted concern about the potential environmental impact of bark-harvesting on the Pacific yew.
Environmentalists, medical groups and others have said they support using the tree's bark as a source for taxol. But they have expressed concern that the tree--already threatened by logging operations in the Pacific Northwest--could be further jeopardized by indiscriminate harvesting of the bark to obtain the drug, a process that kills the tree.
Rep. Ron Wyden (D-Ore.), chairman of the House Small Business subcommittee on regulations, energy and business opportunities, said the agreement left "more questions unresolved than answered." His subcommittee has scheduled a hearing on the issue next month.
The drug will be available only for use in further studies, the National Cancer Institute said. Its marketing as a treatment for any cancers has not been approved by the Food and Drug Administration.
Under the new accord, Bristol-Myers Squibb will be entitled to harvest up to 750,000 pounds of bark each year to produce about 25 kilograms of pure taxol, enough to treat an estimated 12,500 cancer patients in clinical trials, USDA said.
To meet that objective, bark must be removed from about 38,000 yew trees, it said. The Forest Service estimates that there are 23 million Pacific yews on national forest land in western Oregon and Washington alone, the department said.
Bristol-Myers Squibb officials said they will work with the National Forest Service to develop a comprehensive management plan for the Pacific yew, including a program to inventory the trees. The company and the forest service also will draw up conservation guidelines and a research plan to preserve the species.
"We want to make sure we know how many trees there are and where they are," said Kathryn R. Bloom, a company spokeswoman. "Under the agreement, we will provide the funds so government scientists can design and implement a comprehensive research program that deals with the ecology, cultivation and management of the Pacific yew."
The agreement will "enable us to proceed with collection of Pacific yew bark while . . . protecting forest ecosystems and the long-term viability of the species," Madigan said.
But Wyden said: "The company is getting a priority of harvest of up to 750,000 pounds per year. One question is: Can the yew sustain that kind of demand?"
Bloom said the company was "working very, very hard" to find alternative sources for taxol so that "the trees can keep growing" and that reliance on the yew's bark ultimately could be reduced.
Researchers also are trying to develop methods to synthesize the drug.
The cancer institute estimates that it will take two to three years before sufficient taxol is available from other sources to provide some relief from the need to use the bark from yew trees. The institute predicted that it would likely be four to five years before the need for bark is eliminated.
Madigan on Wednesday also signed an order doubling the reward to $10,000 for information leading to the apprehension of individuals who steal Pacific yew bark from national forests.