Kuvan® (sapropterin dihydrochloride): FDA-Approved for Phenylketonuria (PKU)

Filed in archive FDA Approvals , Genetics , Treatment on December 19, 2007

Phenylketonuria (PKU) is a rare genetic disorder that causes mental retardation, smaller brain size, delayed speech and other neurological problems.




If diabetes is characterized by the body not being able to metabolize sugar thereby resulting in high levels of glucose in the blood, PKU is characterized as the body not being able to metabolize phenylalanine (Phe), thereby resulting to high levels of Phe in the blood.

PKU is a genetic disorder in which the enzyme phenylalanine hydroxylase (PAH), which helps our bodies break down phenylalanine (Phe), an amino acid found in foods, does not function properly.

The result is high levels of phenylalanine in the blood. High levels of Phe are toxic to the brain and can lead to mental retardation, behavioral abnormalities, seizures, an inability to focus and organize information, and other neurologic complications.

Now, the US FDA has approved the first drug of its kind that has been found to slow the effects of PKU.

The said drug is Kuvan® (sapropterin dihydrochloride) that was developed by BioMarin Pharmaceutical Inc. (Novato, California, USA) in partnership with Merck Serono - a division of Merck KGaA (Darmstadt, Germany).

Kuvan was first granted orphan drug designation by the FDA in January 2004.

In January, 2006 Kuvan was granted a fast track designation by FDA based on its potential to offer a significant advantage to patients over current treatment options. The Kuvan new drug application (NDA) also received a priority review by FDA.

Kuvan works by increasing PAH enzyme activity in PKU patients with some residual PAH enzyme function. This then leads to an increased breakdown (metabolism) of phenylalanine (Phe), resulting in lower levels of Phe in the blood.

Kuvan must be used in combination with a phenylalanine-restricted diet. A patient can override the effects of Kuvan by not following a Phe-restricted diet.

Find more details from the FDA News and the Biomarin PR.