A reader sends along this article from the New York Times about Chris Kilham, an ethnobiotanist from U. Mass - Amherst looking for medicinally active plants in Peru. The article has lots of local Peruvian color, but it doesn’t neglect the money involved:
” Products that once seemed exotic, like ginseng, ginkgo biloba or aloe vera, now roll off the tongues of Westerners. All told, natural plant substances generate more than $75 billion in sales each year for the pharmaceutical industry, $20 billion in herbal supplement sales, and around $3 billion in cosmetics sales, according to a study by the European Commission.”
It’s worth noting, though, that none of those three once-exotic plants (exotic when – twenty-five years ago?) are the source of any major revenue for the pharmaceutical industry, unless you count aloe-vera sunscreen line extensions and the like. Kilham himself has some definite opinions on the value of plant-derived drugs:
Mr. Kilham believes multinational drug companies underutilize the medicinal properties in plants. They pack pills with artificial compounds and sell them at huge markups, he says. He wants Westerners to use the pure plant medicines that indigenous peoples have used for thousands of years.
“People in the U.S. are more cranked up on pharmaceutical drugs than any other culture in the world today,” Mr. Kilham said. “I want people using safer medicine. And that means plant medicine.”
Unpacking those statements is a chore, though. Just to pick a big one, “pure plant medicine” is a tricky concept, as any natural products chemist will tell you. Are we talking ground whole plants here (and if so, which parts, grown where?) Extracts (and if so, which fractions?) Purified single compounds?
Moving to the next difficulties, would these plant medicines somehow not be sold at such huge markups? Take a look at the herbal supplement industry for a reality check on that one. And if we in the drug industry could get such drugs with less trouble and effort than our “artificial” ones, why wouldn’t we do so – especially if they have fewer side effects? (Side effects cost us money, too, you know). Finally, are those natural compounds really safer than the nasty artificial ones? Not as far as I’ve ever seen – they come out the same in genotoxicity studies, for one thing. The whole “artificial” versus “natural” division is generally a sign of lazy thinking, in my experience. There’s no wholesome Gaia-derived goodness to be found in a plant-derived natural products, and they weren’t somehow made for us to use as medicines. Some are harmless, some are toxic – same as everything else.
Then there’s this interesting part:
“So-called bioprospectors can make their fortunes by bringing those advantages to the attention of companies who identify the plant’s active compound and use it as a base ingredient for new products that they patent.
Some 62 percent of all cancer drugs approved by the Food and Drug Administration come from such discoveries, according to a study by the United Nations University, a scholarly institution affiliated with the United Nations.”
Hmm. Examples? The only “bioprospector” that I can recall making a fortune in this way was Russell Marker, the founder of Syntex, who realized that Mexican yams contained an excellent starting material for steroid synthesis. Mind you, that was in 1944. If anyone has a more recent example of an Indiana Jones figure stumbling out of the jungle clutching a profitable wonder root, please do let me know. Whole companies have been founded on the idea of cashing in on active natural products and indigenous medicines. None of them, as far as I can tell, have made any fortunes yet, and some of them have done the reverse. Shaman Pharmaceuticals is the obvious example. I know someone who was right in the middle of their drug discovery effort. It wasn’t pretty, and it sure wasn’t profitable.
Besides, the Times reporter should have asked Kilham himself about cancer therapies. Here's a 2005 interview with him:
"I don't see the cancer herb category becoming a major category any time soon. I believe that the majority of people who get cancer are still going to turn to a conventional medical doctor. I think the greatest majority will. . ."
And that study by the UN doesn’t appear to have dug all that deeply. (It should be noted up front that oncology and anti-infectives are the two areas where natural product-derived compounds are by far the most well-represented). That 62 per cent figure for cancer drugs would seem to come directly from this 2003 paper in the Journal of Natural Products, from a group at the Natural Products branch of the National Cancer Institute. A closer look at the figures show that they list 140 drugs available over the years 1981-2003 (note that many of these are no longer first-line therapies). The 62% figure comes from excluding all the antibodies, proteins, and vaccines (10% of the total) and counting straight natural products (14%), semisynthetic compounds derived from them (26%) and synthetic compounds whose active pharmacophore came from a natural product lead (14%).
You can draw the line wherever you like, but by rigorously crunchy standards only that first 14% qualifies. If we’re going to draw some line between “natural” and “artificial”, everything else is on the other side of it. There’s no denying that natural products are and have been a great source of active compounds and structural leads, of course. But the vast majority of drugs come from us chemists, cranking out the man-made (and man-improved) structures.
The other problem with that number is that, if anything, it may represent a peak. The kinase inhibitors that have been approved in recent years are all completely synthetic compounds, and the antibody and vaccine ranks are swelling, too. Ranked by sales, there are 19 oncology drugs in the most recent top 200 list I can find, and only one of them is a straight natural product (taxol, at #169). Taxotere, at #37, is a semisynthetic derivative of taxol, and irinotecan at 122 is a semisynthetic as well. But to my eyes, that’s about it. Getting data by usage is harder (without paying for it!), but the older natural products would come out looking better ranked by total prescriptions filled. In most cases, though, they’re no longer first-line therapies.
So natural products aren’t dead, by any means. But they aren’t an untouched gold mine, either. Someone tell the Times.