FDA rates drug made from goat milk safe, effective

WASHINGTON — In what would be a scientific first, an anti-clotting drug made from the milk of genetically engineered goats moved closer to government approval Wednesday after experts at the Food and Drug Administration (FDA) reported that the medication works and its safety is acceptable.

Called ATryn, the drug is intended to help people with a rare hereditary disorder that makes them vulnerable to life-threatening blood clots.

Its approval would be a major step toward new kinds of medications made not from chemicals but from living organisms genetically manipulated by scientists.

ATryn was developed by a Massachusetts biotechnology company, GTC Biotherapeutics, by altering the genes of goats so they would produce milk rich in antithrombin, a protein that in humans acts as a natural blood thinner.

About one in every 5,000 people don't produce enough of the protein, putting them at risk of developing blood clots in their veins.

Such clots can be extremely painful. If they break loose and travel through the bloodstream to the lungs or the brain, the consequences can be catastrophic. Pregnant women with the disorder are at high risk of miscarriage or stillbirth, because of blood clots in the placenta.

In their everyday lives, patients with antithrombin deficiency are managed with conventional blood thinners. That would not change. ATryn is for use only when patients are having surgery or having a baby, times when the risk of dangerous clots is particularly high.

"It's the first time we've held an advisory committee meeting on any product from a genetically engineered animal," FDA spokeswoman Siobhan DeLancey said.

If the drug is approved, the FDA may require follow-up monitoring to make sure that patients' immune systems don't start making antibodies in reaction to the medication.