BioMarin Pharmaceutical received FDA approval for a Supplemental Biologics License Application (sBLA) for the use of Palynziq (pegvaliase-pqpz) in adolescents 12 years of age and older with phenylketonuria (PKU).[1][2][3] Palynziq is the only enzyme replacement therapy approved to reduce blood levels of phenylalanine (Phe) in patients with PKU.[1][2][5] The approval is based on data from the pivotal phase 3 PEGASUS study, which compared Palynziq to diet alone in adolescents with uncontrolled Phe levels above 600 µmol/L.[1][2][4] At the end of the first part of the study, 44.4% of participants had Phe levels below the recommended values, with 75% falling below 120 µmol/L, with an average drop of 828 µmol/L (94% from baseline).[2] In the nine participants with hypophenylaninemia, intact protein intake increased by 318.1% and dietary protein intake decreased by 55.16%; six gave up medical nutrition altogether.[2] The most common adverse reactions included joint pain, dizziness, fatigue, hypersensitivity, nausea, fever, and vomiting.[2][4] BioMarin is also seeking approval from the European Medicines Agency (EMA) to extend its use to adolescents from 12 years of age in the EU.[1][2][3]