Latebreakers: First drug approved for treatment of phenylketonuria

January 14, 2008

Sapropterin approved for phenylketonuria treatment

The FDA and Biomarin Pharmaceutical Inc. have announced the approval of sapropterin (Kuvan), the first new molecular entity given a regulatory nod for the treatment of phenylketonuria (PKU), a condition that affects about 50,000 patients worldwide. Sapropterin is the synthetic form of 6R-BH4 (tetrahydrobiopterin), an enzyme cofactor that works with phenylalanine hydroxylase to metabolize phenylalanine. Prolonged exposure to high levels of phenylalanine can result in severe neurological damage. The drug has received seven years of market exclusivity as an orphan drug from the FDA. According to the manufacturer, not all patients with PKU will respond to sapropterin, but a therapeutic trial with the drug can determine who will benefit. Sapropterin should be used in conjunction with a phenylalanine-restricted diet.