FDA approves drug produced in transgenic chickens

GE chickens produce specialized protein in egg whites that is purified for treatment of rare childhood disease.

The U.S. Food & Drug Administration announced Dec. 8 that it has approved Kanuma (sebelipase alfa) as the first treatment for patients with a rare disease known as lysosomal acid lipase (LAL) deficiency.

Patients with LAL deficiency, also known as Wolman disease, have no or little LAL enzyme activity, which results in a build-up of fats within the cells of various tissues that can lead to liver and cardiovascular disease and other complications.

The approval involved approvals from two centers at FDA. The Center for Veterinary Medicine (CVM) approved an application for a recombinant DNA (rDNA) construct in chickens that are genetically engineered (GE) to produce a recombinant form of human lysosomal acid lipase (rhLAL) protein in their egg whites. FDA regulates GE animals under the new animal drug provisions of the Federal Food, Drug, & Cosmetic Act, because an rDNA construct introduced into an animal to change its structure or function meets the definition of a drug.

The Center for Drug Evaluation & Research (CDER) approved the human therapeutic biologic (Kanuma), which is purified from those egg whites, based on its safety and efficacy in humans with LAL deficiency.

“LAL deficiency is a rare inherited genetic disorder that can lead to serious and life-threatening organ damage, especially when onset begins in infancy,” said CDER Director Janet Woodcock, M.D. “Using this technology, these patients for the first time ever have access to a treatment that may improve their lives and chances of survival.”

The new therapy, Kanuma, is produced by GE chickens containing an rDNA construct responsible for producing rhLAL protein in their egg whites. These egg whites are refined to extract the rhLAL protein that is eventually used to produce Kanuma and treat patients with LAL deficiency. The GE chickens are used only for producing the drug substance, and neither the chicken nor the eggs are allowed in the food supply.

In its review of the GE chicken application, CVM assessed the safety of the rDNA construct, including the safety of the rDNA construct to the animals, as well as a full review of the construct and its stability in the genome of the chicken over several generations. No adverse outcomes were noted in the chickens. As required by the National Environmental Policy Act and its implementing regulations, CVM evaluated the potential environmental impacts of approval of the sponsor’s GE chickens and determined that the approval does not cause any significant impact on the environment, because the chickens are raised in highly secure indoor facilities.

“We reviewed all of the data to ensure that the hens do produce rhLAL in their egg whites, without suffering any adverse health effects from the introduced rDNA construct. The company has taken rigorous steps to ensure that neither the chickens nor the eggs will enter the food supply, and we have confirmed their containment systems by inspecting the manufacturing facilities,” CVM director Dr. Bernadette Dunham said.

Kanuma is produced by Alexion Pharmaceuticals Inc., based in Cheshire, Conn.

FDA previously approved a blood clot-forming drug produced in the milk of GE goats.

Hide comments

Comments

  • Allowed HTML tags: <em> <strong> <blockquote> <br> <p>

Plain text

  • No HTML tags allowed.
  • Web page addresses and e-mail addresses turn into links automatically.
  • Lines and paragraphs break automatically.
Publish