Genetically engineered chickens produce eggs used in new human drug

The U.S. Food and Drug Administration (FDA) has approved a new drug called Kanuma (sebelipase alfa) as a treatment for patients with a rare disease called lysosomal acid lipase (LAL) deficiency, according to an agency release.

The approval involved the efforts of two FDA centers, the Center for Veterinary Medicine (CVM) and the Center for Drug Evaluation and Research (CDER). The CVM approved an application for a recombinant DNA (rDNA) construct in chickens that have been genetically engineered to produce a recombinant form of human lysosomal acid lipase protein in their egg whites. The FDA regulates genetically engineered animals under the new animal drug provisions of the Federal Food, Drug and Cosmetic Act-an rDNA construction introduced into an animal to change its structure or function meets the definition of a drug. The 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.

The genetically engineered chickens are used only for producing the drug substance, and neither the chicken nor the eggs are allowed into the food supply.

Patients with LAL deficiency (also known as Wolman disease and cholesteryl ester storage disease) have little or no LAL enzyme activity, which leads to a buildup of fats in tissue cells and can lead to liver and cardiovascular disease. Wolman disease often presents during infancy and is rapidly progressive-patients rarely survive beyond the first year of life, according to the FDA release. Cholesteryl ester storage disease is a milder, later-onset form of LAL deficiency, with life expectancy dependent on severity of the disease.

The newly approved therapy provides a recombinant form of human LAL protein that functions in place of the missing or inactive LAL protein in human patients.

The CVM's review assessed the safety of the rDNA construct to the chickens, as well as a the construct's stability in the chicken genome over several generations. No adverse outcomes were noted, according to the release. The CVM also evaluated the potential environmental impact of the genetically engineered chickens and found that they did not cause a significant impact on the environment because they  are raised in secure indoor facilities.