With its decision to approve genetically modified (GM) salmon not even a month old, the FDA is advancing science once again. This time officials have approved a GM chicken, but this approval is much different than the last.
AquaBounty's GM salmon, which contains genes from other salmons so it grows big fast, is intended for human consumption. GM chicken did not gain approval for human consumption of the chicken or the eggs -- and the company that created it, Alexion Pharmaceuticals, wasn't trying.
Instead, Alexion's GM chickens received approval to serve as manufacturers of the drug Kanuma (sebelipase alfa), which treats a rare genetic condition called lysosomal acid lipase deficiency (LALD). The GM chickens will produce Kanuma in their egg whites, and then the drug can be isolated from the eggs to be administered to patients.
People with LALD lack an enzyme that helps them break down certain fats, left untreated these fats accumulate in the body and interfere with normal cellular function. Left untreated, infants do not live too long. Adults can acquire the affliction too, which occurs in 1 in 40,000 Americans.
The use of organisms of drug making machines is not new. For decades insulin production for diabetics has been primarily made through GM E. coli. In 2009, the FDA approved GM goats, whose milk produced a human blood protein, antithrombin, for the treatment of various blood-clotting disorders. Last year, the agency also approved GM rabbits which produced milk containing the drug Ruconest for treatment of angioedema.
Kanuma is a biopharmaceutical, or biologic, for short. These are drugs made by or extracted from a living source. Vaccines are biologics, as are antibody treatments. The genetic template inserted into the chickens is the human gene that codes for the enzyme lysosomal acid lipase. In general, biologics are an expensive business. Many are made in cell cultures in labs that do not have great yields of the protein. The advantage with having chickens produce the enzyme is that the yield is significantly higher than the cell culture. Instead of keeping a bunch of cell cultures around a lab, a farm will house a large group of these GM chickens which will be constantly laying eggs (and thus producing the drug) over their entire lifespan.
This is an expensive drug, so a better, cheaper way to produce it is a great use of this technology -- but don't get your feathers in an uproar about the chance to eat a GMO egg just yet.