A Phase 3b Open-Label Study of Long-Term Neurocognitive Outcomes in Children With Phenylketonuria Treated With Sepiapterin
The main purpose of this trial is to evaluate the long-term efficacy of sepiapterin on preserving neurocognitive functioning in children with PKU when treatment is initiated in early childhood.
⁃ For all participants:
• Women of childbearing potential must have a negative pregnancy test at screening and agree to abstinence or the use of at least one highly effective form of contraception for the duration of the study, and for at least 90 days after the last dose of the study drug.
• Willing to maintain prescribed daily protein/Phe during Screening and Part 1.
• Established diagnosis of PKU with hyperphenylalaninemia (HPA) evidenced by at least 2 blood Phe measurement ≥600 micromoles (μmol)/liter (L) as documented in the medical history.
• For participants ≥1 month of age at Screening: A minimum of 1 documented blood Phe measurement \<480 μmol/L within 1 month prior to Screening.
• For participants ≥1 month of age at Screening: Two screening blood Phe concentration values must be in the range ≥120 to ≤480 μmol/L.
⁃ For participants \<1 month of age at the time of informed consent/assent only:
• Blood Phe at newborn screening ≥600 μmol/L.
⁃ For participants ≥30 months to \<10 years of age:
• Baseline FSIQ score ≥80.