Drugs from genetically-engineered goats

Drugs have been derived from animals for quite some time now. The latest is a drug meant to prevent fatal blood clots in people, which has been developed from the milk of genetically engineered goats. The goats generate the human protein antithrombin, which inhibits clotting. The US Food and Drug Administration has approved the drug called ATryn, the first produced by livestock that have been given a human gene.

Why should I be aware of this?

• This is the first drug from a herd of genetically engineered animals created specifically to serve as living pharmaceutical factories.
• Similar drugs could be available in the next few years for a range of human ailments, including hemophilia.
• As there is tremendous shortage of human plasma donations, the protein in the Goat Milk, antithrombin, is sometimes in short supply or unavailable for pharmaceutical use. It is estimated by the manufacturers of the drug, GTC Biotherapeutics , that one of its goats can produce as much antithrombin in a year as can be derived from 90,000 blood donations.

Drugs from genetically-engineered goats and health

There are also the following major health concerns.

• It is feared that the animals could be harmed,
• that animal germs might contaminate the drug,
• that the milk or meat from genetically engineered drug-producing animals might enter the food supply
• that the animals might escape and breed with others, spreading the gene, with unpredictable consequences.

All about drugs from genetically-engineered goats

A herd of 200 bioengineered goats living under carefully controlled conditions on a farm in central Massachusetts have been used to produce the human anticlotting protein.

Making process

The FDA has approved the drug which will prevent blood clots in people born with a rare hereditary deficiency of antithrombin while they undergo surgery or childbirth. At other times such people can reduce their clotting risks by taking blood thinners like warfarin, but during surgery or childbirth blood thinners are typically avoided because of the risk of excessive bleeding.

To make its protein, GTC took the human gene for antithrombin and linked it to goat DNA that normally controls production of a protein found in milk. That ensured that the antithrombin would be produced only in the milk.

The gene was injected into a one-celled goat embryo, which was then implanted into the womb of a surrogate mother. After a goat was born that produced the protein in its milk, the herd was expanded by conventional breeding.

Animal-derived drugs

By this method large quantities of biotechnology drugs can be produced at a much lower cost than the existing methods — which include extracting proteins from donated human blood or growing them in large steel vats of genetically engineered cells.

Earlier too drugs have been derived from animals. Most insulin used to treat diabetes earlier came from pigs or cows. Genetically engineered mice are now used to develop some drug ingredients.

90 degrees

Some environmental advocates and animal rights activists are opposed to using animals for drug production. They protest against the mechanistic use of animals that perpetuate the notion of their being merely tools for human use rather than sentient creatures.

Unlearn

One risk of using animals is that drug production can be lost if a disease wipes out the herd.

References:

• F.D.A. Approves Drug From Gene-Altered Goats
• Whatever Happened to Drugs from Goats?
• Drug From Milk of Genetically Engineered Goats Gets OK