FDA Approves Sephience (sepiapterin) for PKU Treatment in Adults and Children

The Food and Drug Administration (FDA) has granted approval for Sephience™ (sepiapterin) as a treatment option for hyperphenylalaninemia (HPA) in both adults and children aged one month and older diagnosed with sepiapterin-responsive phenylketonuria (PKU). Sepiapterin functions as an activator of phenylalanine hydroxylase (PAH), helping to lower blood phenylalanine (Phe) levels by boosting intracellular tetrahydrobiopterin (BH4) concentrations and preventing PAH enzyme misfolding. This approval follows the successful completion of the two-phase phase 3 APHENITY trial (ClinicalTrials.gov Identifier: NCT05099640), which assessed the drug's effectiveness in patients from 1 to 61 years old with PKU and elevated Phe levels of at least 600μmol/L. In the initial part of the study, 157 participants received daily open-label doses of sepiapterin at varying amounts based on age: 7.5 mg/kg for infants under 6 months, 15 mg/kg for those between 6 and 12 months, 30 mg/kg for children from 12 months to under 2 years, and 60 mg/kg for individuals aged 2 years and older, over a period of 14 days. Results indicated that 66% of these participants experienced at least a 30% reduction in blood Phe le...