Planet Biotechnology is in clinical trials of an antibody, produced in genetically altered tobacco, that blocks the bacteria that cause tooth decay. Elliott L. Fineman, the chief executive, said it would be impossible to use mammalian cells to produce the 600 kilograms a year that might be needed in a cost-effective way. But the entire supply could be affordably produced on a single large tobacco farm. Still, the companies wanting to grow drugs have found the going somewhat rough. The Large Scale Biology Corporation, formerly Biosource Technologies, did the first field test of a drug produced by a plant in 1991 but still does not have a drug in clinical trials.
Drug companies are hesitant to depart from existing technology.
And some industry experts are not convinced that plants would be cheaper when the cost of extracting the drug from the plant is considered. Moreover, the production of drugs in plants faces competition from production in the milk of genetically modified animals. This also offers potentially high volumes at low costs, and the animal milk companies are closer to bringing products to market. Some already have deals signed with major drug companies. The plant-drug companies say their technique is safer because mammalian cells and animal milk can introduce harmful viruses into the drug, while plant viruses are not known to infect people.