Taking the Chinese Approach
Chinese doctors have long tinkered with combinations of herbs to cure disease. If a plant extract helped fight an infection, why bother trying to figure out which molecule did the trick? It worked, and that's what counted.
By contrast, the U.S. Food and Drug Administration, one of the world's most stringent drug watchdogs, for decades turned up its nose at applications for herbal medicines. The focus in Western pharmacology was finding the single compound to cure a disease. Pharmaceutical companies such as Pfizer and Merck spend billions of dollars combing through libraries of thousands of compounds to find the elusive blockbuster therapy.
The different approaches boil down to a simple question: Do you attack disease, as the Western world does, with a silver bullet -- a single compound whose potency you've pinpointed? Or do you use the Chinese method, aiming a group of agents at the disease target -- a shotgun approach?
The FDA was less receptive to latter method. The agency held botanical drugs to the same rigid standard as other therapies: find the part that works and prove it. Chinese medicines and other plant-based, or botanical, therapies, such as ginkgo and Echinacea, were sidelined to the dietary-supplement shelves at supermarkets and kept out of pharmacies.
But lately, the agency has edged closer toward the Chinese approach. In June 2004, it issued new guidelines making it easier for drug companies to turn herbal remedies into Western medicines.
Late last year, the FDA approved its first botanical drug under the new system, an ointment for genital warts called Polyphenon E, made from green-tea leaves.
The key change was requiring companies looking to convert plant-based extracts into marketable prescription drugs only to purify a plant extract, which could contain hundreds of compounds, rather than pinpointing a single one. 'There were so many stories of potentially new treatments in alternative medicine ... we needed a different approach than dealing with a single small molecule,' says Shaw T. Chen, botanical team leader at the FDA.
This new openness has led a surge of applications for approvals, and resulted in clearance for clinical trials for about 250 botanical drugs at some stage in the pipeline, most derived from traditional Chinese medicine.
The FDA even established a special office to deal with all those applications. To help run it, it has hired experts with training in herbal medicines. Jin hui Dou, for instance, a drug reviewer for the FDA's newly formed botanical review team, was born in China and earned a degree from the Beijing University of Chinese Medicine.
It's hard to predict how successful other applications are going to be. The standards for clinical testing of these herbal remedies in humans remain unchanged. And proving the effectiveness of these therapies overall is still a big challenge for the manufacturers.
Phynova, for example, a small, British drug-research company, has gotten the green light from the FDA to test a hepatitis botanical drug. The drug is a combination of four different plants: the roots of the astragalus and the Chinese salvia plants, the fruit of the schisandra plant, and milk thistle.
The number of compounds contained in each of those distilled extracts varies from several hundred to more than a thousand. So it's difficult to know which chemical is doing what. 'It could take somebody's whole life to figure that out,' says Robert Miller, Phynova's chief executive.
One advantage of attacking multiple targets with different compounds is that our body, and the pathogens that try to invade them, often evolve several layers of redundancy, the equivalent of a back-up power generator that flicks on when a fuse blows.
That goes a long way in explaining why it's been so difficult to come up with a powerful antiobesity drug. There are multiple ways our bodies register hunger. When patients are given appetite-suppressants, for example, their bodies often compensate by slowing down their metabolism. If hunger were easy to shut off, evolving human beings could easily have died of starvation.
Chinese medicine encompasses a huge swath of treatments and practices -- everything from acupuncture to remedies such as dried deer penis pulverized and taken as tea. An incomplete understanding of how a medicine works can make it harder to ensure its safety or to predict side effects. And there are good reasons to doubt many therapies, as a well as a danger of fetishizing so-called alternative approaches.
Polyphenon, the genital warts remedy, probably has 10 or 20 major active components and hundreds of molecules, according to Dr. Chen. 'There's a theoretical possibility that there are multiple active ingredients in botanicals that act on multiple systems that have synergistic effects,' he says. 'But that remains to be proved.'
Nicholas Zamiska