Genetically modified chickens, which can produce a drug in their eggs, have been approved by the U.S. Food and Drug Administration (FDA). The drug in question, called Kanuma, will be used to treat a rare disease of humans that often proves fatal for infants. The chickens, which themselves are technically classified as “animal drugs” by the FDA, will not be used for human consumption, and will be bred and kept in a lab.
Lysosomal acid lipase (LAL) deficiency is a rare genetic disease in which the body does not produce enough of the LAL enzyme. This means that the body cannot break down fatty material, which then builds up in the liver, spleen, and vasculature. It comes in two different forms, with the first affecting babies, usually around two to four months of age. Known as Wolman disease, it is rapidly progressive and is often quickly fatal. The second form, known as cholesteryl ester storage disease (CESD), is later in onset, normally occurring in early childhood but also in adults. Depending on the severity of the CESD, this form can be managed.
Currently, treatment for the disease targets the symptoms, not the cause. This is where the transgenic chickens come in. They have been genetically modified to produce eggs in which the white portion contains a form of the human LAL enzyme. The pharmaceutical company can then take the white and refine it to get the enzyme, known commercially as the drug Kanuma, and then use this to treat those suffering from LAL deficiency, before the fat can build up and cause complications.
“LAL deficiency is a rare inherited genetic disorder that can lead to serious and life-threatening organ damage, especially when onset begins in infancy,” explains Janet Woodcock, the Director of the Center for Drug Evaluation and Research, in a statement. “Using this technology, these patients for the first time ever have access to a treatment that may improve their lives and chances of survival.”
Now that the chickens have been approved by the FDA, they join only a handful of other animals, known by some as “farmaceuticals.” Already on the U.S. market are GM goats, which produce an anticoagulant in their milk, and a drug produced in rabbits, which is used to treat angioedema – the rapid swelling of skin on the face and in the mouth. Although none of these animals are on the public market for consumption and are confined to labs, this year also saw the historic approval by the FDA of genetically modified salmon for food.
Interestingly, the GM chickens were fast-tracked through the approval process, and some think that this could open up the way for more transgenic animals that produce drugs to hit the market, proving that the goat and rabbit were not simply a one off.