Sephience FDA Approval History
Last updated by Judith Stewart, BPharm on July 29, 2025.
FDA Approved: Yes (First approved July 28, 2025)
Brand name: Sephience
Generic name: sepiapterin
Dosage form: Oral Powder
Company: PTC Therapeutics, Inc.
Treatment for: Phenylketonuria
Sephience (sepiapterin) is a phenylalanine hydroxylase activator used for the treatment of patients with phenylketonuria.
- Sephience is indicated for the treatment of hyperphenylalaninemia (HPA) in adult and pediatric patients 1 month of age and older with sepiapterin-responsive phenylketonuria.
- Phenylketonuria (PKU) is a rare, metabolic disease caused by a defect in the gene that helps create the phenylalanine hydroxylase (PAH) enzyme needed to break down phenylalanine. Phenylalanine is an essential amino acid found in all proteins and most foods, and if it builds up to harmful levels in the body can cause severe and irreversible disabilities such as permanent intellectual disability, seizures, delayed development, memory loss, and behavioral and emotional problems. Diagnosis of phenylketonuria usually takes place during newborn screening programs.
- Sephience contains sepiapterin, which works to reduce blood phenylalanine levels in patients with phenylketonuria by increasing activity of the PAH enzyme. It has a dual mechanism of action as a precursor compound that is rapidly absorbed and converted intracellularly to tetrahydrobiopterin (a critical cofactor of PAH) and also has an independent chaperone effect, protecting against PAH misfolding to enhance the enzyme function.
- FDA approval of Sephience was based on the evidence of significant efficacy and safety from the Phase 3 APHENITY trial as well as durability of treatment effect in the APHENITY long-term extension study.
- Sephience oral powder is mixed with the required volume of water or apple juice and administered once daily with food.
- Sephience is used in conjunction with a phenylalanine (Phe)- restricted diet.
- Warnings and precautions associated with Sephience include an increased risk of bleeding and hypophenylalaninemia.
- Common adverse reactions (≥2% and greater than placebo) include diarrhea, headache, abdominal pain, hypophenylalaninemia, feces discoloration, and oropharyngeal pain.
Development timeline for Sephience
Further information
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