WebMD Health News
Louise Chang, MD
Feb. 6, 2009 -- The FDA today approved ATryn, the first drug made in
genetically engineered animals.
ATryn, which is given by infusion, is for people with a rare condition
called hereditary antithrombin deficiency. About 1 in 5,000 people in the U.S.
have that condition, according to the FDA.
People with hereditary antithrombin deficiency don't make enough
antithrombin, an anticlotting compound. That shortfall of antithrombin puts
patients at risk of life-threatening blood clots, especially during pregnancy, childbirth, surgery, or prolonged bed rest.
ATryn comes from goats that were genetically engineered to have human
antithrombin, an anticlotting protein found in healthy people, in their
Patients won't drink that goat milk. The human antithrombin is extracted
from the goats' milk to make ATryn.
The FDA approved ATryn based on two studies of 31 patients with hereditary
antithrombin deficiency to prevent dangerous blood clots before, during, or
after surgery or childbirth. All but one of those patients had a history of
such clots, which are likely to recur in high-risk situations if left
untreated. Only one of the 31 patients had a clot when treated with ATryn.
The most commonly reported adverse reactions to ATryn were hemorrhage and
infusion site reactions. Those reactions occurred in about 5% of the patients
studied, according to the FDA.
The FDA's Center for Veterinary Medicine also found that the genetic
engineering process didn't have adverse effects on seven generations of the
goats and that GTC Biotherapeutics has adequate procedures in place to ensure
that food from those goats doesn't enter the food supply; it also found that
the goats won't harm the environment.
The FDA's approval of ATryn is in line with the recommendation made by an FDA
advisory committee last month.
GTC Biotherapeutics developed ATryn and granted ATryn's U.S. marketing
rights to Ovation Pharmaceuticals. In a joint news release, GTC Biotherapeutics
and Ovation Pharmaceuticals note that ATryn is approved for the prevention of
clotting events around the time of surgery and childbirth in patients with
hereditary antithrombin deficiency, but not to treat clots in those
Other treatment for hereditary antithrombin deficiency involves taking blood
thinners and getting infusions of human antithrombin that's been extracted from
donated human blood.
SOURCES:News release, FDA.WebMD Medical News: "FDA
Panel OKs Drug From Goats."News release, GTC Biotherapeutics, Inc. and Ovation Pharmaceuticals,
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