Science & Technology
THE MEDICINE MAN WILL SEE YOU NOW
Sophisticated screening targets and laboratories run by robots may help big companies discover drugs more efficiently. But tiny Shaman Pharmaceuticals Inc. in San Carlos, Calif., has a different idea. It takes a less-traveled route to finding the specimens it tests as potential drugs. Shaman sends scientists into jungles, primarily in Latin America, to interview traditional healers about the potions they derive from rain-forest plants. High-tech it isn't, but the strategy has centuries of satisfied customers going for it.
This approach to getting leads is called "ethnobotany," the study of how native cultures use plants. Shaman's researchers comb scientific literature for references to plant extracts that have medicinal value. Then, they ask real shamans how they would treat various ailments--even showing them photographs of patients with obvious symptoms, such as herpes sores. "The big investment we put into ethnobotany pays off," claims Shaman's chief executive, Lisa A. Conte. "Big companies may randomly screen thousands of plants, where we only screen 75 a year." Yet Shaman comes up with an initial "hit" about half the time, vs. a minuscule fraction of that in random-screening programs.
IMPRESSIVE PROGRESS. In fact, though it's only four years old, the company already has two drugs in clinical trials. Traditional healers use a plant from the rain forests of Peru, Ecuador, and other South American countries to treat maladies ranging from colds to wounds. When Shaman tested this still-secret weed, it found that it is a virus-fighter. Now, extracts from the weed have become SP-303, a drug that is being tested on people as a treatment for RSV, a deadly respiratory disease that attacks children. Shaman is also testing a related compound as a herpes treatment. That's impressive progress for such a relatively recent startup--and it helped Shaman raise $41 million in an initial public offering in January.
Other companies are taking note of Shaman's progress. Ethnobotanists such as Michael Balick, director of the Institute of Economic Botany at the New York Botanical Garden, report that large drugmakers are increasingly turning to flora and fauna for leads, too. "At least once a week, we get a call from a drug company interested in sourcing a plant," Balick says. Yet the practice of relying on native healers may remain on the fringes of drug development--for good reason. Real sha- mans do best with diseases that have obvious manifestations, such as infections, fevers, or pain. They don't know much about complex genetic diseases or cancers. It is also hard to find and purify the active compound in a traditional healer's mashed- up plant poultices, which may contain many
Diversity. Moreover, some experts argue that confining the new-drug search to cultural uses of plants is too narrow an approach. Robert Thomas, chairman of Biotics Ltd. in Brighton, England, says that when looking for leads among natural chemicals, what's particularly important is to consider a diversity of plant samples. (Biotics is a broker between plant suppliers and screening labs looking for natural samples to test.) Thomas argues that running a large-enough number of chemicals through automated screening systems yields "leads every bit as good as those from ethnobotany."
If you can't afford giant robotic systems and huge libraries of natural chemicals, however, Shaman's approach makes sense. It may also help relieve poverty and preserve rain forests, since Shaman has set up a foundation that will put money back into the indigenous cultures that supply the company's leads. Shaman also employs local people to harvest its plants. There's another new concept: Politically correct drug research.Joan Hamilton in San Francisco