Recombinant Human Antithrombin – Milking Nanny Goats for Big Bucks

Antithrombin deficiency is a hereditary disease causing low levels or defects of antithrombin, a blood protein required for controlling clot formation. Patients are at risk of blood clots, organ damage, and death. They usually have to take oral anticoagulant drugs like warfarin for life.

During high-risk procedures like surgery or childbirth, oral anticoagulants must be discontinued to minimize the chance of bleeding complications. While patients are off oral anticoagulants, they are given preventive treatment with antithrombin derived from pooled human blood. With any human blood product there is a small risk of infection with diseases like hepatitis C. And human antithrombin supplies are not plentiful.

Clever researchers found an ingenious solution. Put a human antithrombin gene in goats, milk them, isolate the human antithrombin protein from the milk, and voila! An udderly safe and plentiful source. A Brit might call it bleatin’ brilliant.

Yes, transgenic goats. No, they are not human/goat hybrids, despite a recent report that a goat had given birth to a human faun in Zimbabwe.

Sex between humans and animals does happen, but it can’t result in pregnancy because of the chromosome differences and other factors. 28% of men with bestial desires are attracted to goats. Goats come fourth after canines, equines and bovines.

You probably don’t know anyone who practices bestiality, but that doesn’t mean it doesn’t happen. I was e-mailed a video clip filmed by a Marine unit in Iraq, a light magnified night image (Improved Thermal Sight System). The marines were monitoring a known Taliban safe house. When they saw a suspect acting strangely, they thought he might be emplacing an IED. As they filmed him, they realized he was copulating with a donkey. They caught the whole thing on video. The best part is their comments as they watch the blurry images and gradually realize what they are seeing. It was apparently on YouTube briefly before it got banned. There is a similar clip with two Iraqis, one holding the donkey, that hasn’t been banned yet.  Of course, I can’t guarantee this isn’t video trickery. But in 2005 there was a well-documented case of a man who died after having sex with a horse just a few miles from where I live. Washington State is one of 17 states where sex with animals is not against the law. Instead of choosing a receptive female equine, this unfortunate man chose a stallion. The man died of a perforated colon; the horse suffered no physical damage, although I suppose we could speculate about possible psychological damage…  The whole thing was caught on videotape. Now there is even a movie. I report the facts without judgment: humani nihil a me alienum puto.

Pardon the prurient diversion. Back to the subject. Transgenic goats can’t be created by such “natural” methods: they require complicated tricky maneuvers in the lab. They are just like normal goats in every respect except that they produce one human protein, antithrombin. Still, it’s a wonder the religious fundamentalists haven’t been denouncing the evil scientists and bombing goat labs. Do they even know about this?

The recombinant human antithrombin is marketed under the brand name ATryn. It has been approved by the FDA for patients with antithrombin deficiency who are undergoing surgery or childbirth. Two clinical studies were done with 5 and 14 patients, respectively. Small studies, but it didn’t seem to call for a lot of investigation since it only amounted to replacing one of the patients’ own deficient proteins. No serious adverse events were reported.

The Medical Letter has evaluated ATryn (Volume 51, issue 1323, October 19, 2009. pages 83-63) and concluded it is a safe and effective source of replacement that may well turn out to have additional therapeutic applications.

Only one problem. It costs $2.34 per international unit, and patients in one study received anywhere from 39,200 IU to 294,000 IU. That adds up to $91,728 to $687,960 for one course of treatment for one patient. The manufacturer has a patient assistance program, but WOW! That’s a lot of money to protect one patient during childbirth! We don’t yet know how many patients will need to be treated to prevent one blood clot or save one life.

I can’t stop thinking about this. I am constantly amazed at the cost of some of the new drugs with limited applications, especially chemotherapy. And it’s not just the new, limited-use drugs. I recently got a prescription for what I thought was a cheap old antibiotic long available as a generic, and I was appalled at the price. It was more than ten times what I would have guessed.

It’s wonderful that science can accomplish such feats, and I have no ethical qualms about using goats as factories to help humans, but I wonder about the ethics of saddling society with unaffordable bills for treatments that provide only a small advantage. As we develop more of these expensive drugs, we could go bankrupt trying to provide them for every patient. It’s a dilemma that bears thinking about before it happens. One of the 4 basic principles of medical ethics is justice, or fair distribution of medical services to society.

However you look at it, our technical ability will eventually outrun our ability to pay.

This article was originally published in the Science-Based Medicine Blog.

Dr. Hall is a contributing editor to both Skeptic magazine and the Skeptical Inquirer. She is a weekly contributor to the Science-Based Medicine Blog and is one of its editors. She has also contributed to Quackwatch and to a number of other respected journals and publications. She is the author of Women Aren’t Supposed to Fly: The Memoirs of a Female Flight Surgeon and co-author of the textbook, Consumer Health: A Guide to Intelligent Decisions.

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