Scientists have had concerns about animal-derived drugs for some time now; however, they also know creating synthetic alternatives has not always been successful. The recent recall of the Baxter International blood thinner heparin—linked to dozens of deaths and hundreds of illnesses—whose main ingredient comes from pig intestines, has increased public awareness that some important medicines still generate from animals. Although the heparin catastrophe turned out not to be linked to pigs, Scientific Protein Laboratories—supplier of the active ingredient in heparin to Baxter—also supplies much of the pig-derived pancreatic enzymes used by cystic fibrosis patients.
Most cystic fibrosis patients take five large capsules at each meal to supply enzymes their bodies do not produce. This medication is life sustaining for most of the nearly 30,000 people in the US with cystic fibrosis, a hereditary disease that attacks the lungs and digestive tract. Leslie Hendeles, a University of Florida professor of pharmacy and pediatrics asks, “What would happen if there were a virus, a pig virus, something analogous to mad cow disease?” “A number of pharmaceutical firms are trying to eliminate all animal-sourced products from their raw material streams,” said Dr. Robert G. Rohwer, the director of a Department of Veterans Affairs neurovirology laboratory.
Currently, the Cystic Fibrosis Foundation is pursuing an alternative to pig-derived medications and is working with Altus Pharmaceuticals of Cambridge, Massachusetts, to develop a synthetic version of the enzyme capsules. Synthetic replacements are also being sought for other products, including the lung fluids called surfactants used in neonatal wards and for raw materials used in pharmaceutical production. Survanta, the most widely used lung surfactant for premature infants in the US, which is made by Abbott, comes from cows in New Zealand, an island thought to be safe from mad cow disease. Altus is in final stages of clinical studies and is planning to submit its new drug application with the FDA next year. Instead of five large pills with each meal and snack, people with cystic fibrosis would have to take only one small capsule.
Millions of heparin vials are used annually in this country to prevent blood clots during major surgery and kidney dialysis. To date, no appropriate synthetic version has been found. Arixtra, a synthetic drug marketed by GlaxoSmithKline copies the most active portion of heparin, has been successfully used for some surgeries, but it is about 10 times as expensive as heparin and has no specific antidote to reverse its anti-clotting properties if a patient develops bleeding problems.
While the risk of transmitting disease from animal-based drugs is small, it does occur, according to Paul W. Brown, a retired National Institutes of Health senior investigator. “Any time you take a tissue or an extract process from a tissue from one species and put it into a another species or even another animal, you run the risk of unwanted pathogens that you didn’t know were there; that’s been responsible for repeated problems over the course of time,” Dr. Brown said. “If you can do something without taking tissue or a product from another being, you’re ahead of the game.”
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