Recently, the FDA approved Palynziq (pegvaliase-pqpz; BioMarin Pharmaceutical Inc.), a phenylalanine-metabolizing enzyme indicated to reduce blood phenylalanine concentrations in adult patients with phenylketonuria (PKU) who have uncontrolled blood phenylalanine concentrations on existing management.
PKU is a rare genetic disorder that affects 1 in 10,000 to 15,000 persons. PKU is caused by a defect in the PAH gene that helps create the enzyme needed to break down the amino acid, phenylalanine. Phenylalanine is present in protein-containing foods and in certain sweeteners used in a variety of foods and beverages. When the activity of this enzyme is reduced, phenylalanine from the diet is not processed effectively. As a result, phenylalanine can build up to toxic levels in the blood and other tissues. Because nerve cells in the brain are particularly sensitive to phenylalanine levels, excessive amounts of this substance can cause brain damage.
In the United States, babies are routinely screened for PKU shortly after birth. Due to early screenings, this rare genetic disorder can be diagnosed to allow for treatment to begin after birth. Vigilant supervision of foods is necessary to allow for a “normal” lifestyle.
A Hayes Technology Prognosis Overview on Palynziq is available here.