PTC Therapeutics Reveals FDA Action Date for Sepiapterin and Phase 3 Trial Results Publication

WARREN, N.J., Oct. 14, 2024 -- PTC Therapeutics, Inc. (NASDAQ: PTCT) revealed that the FDA has established a target date of July 29, 2025, for the assessment of the New Drug Application (NDA) for sepiapterin. This timeline aligns with the standard review process. The NDA has been submitted for treating both pediatric and adult patients with phenylketonuria (PKU), encompassing all age brackets and the full range of disease variations. Additionally, PTC announced that findings from the Phase 3 APHENITY trial have been published in The Lancet, a leading peer-reviewed medical journal.

Matthew B. Klein, M.D., CEO of PTC Therapeutics, highlighted the significance of The Lancet publication, noting that the data collected on sepiapterin shows its transformative potential to address the ongoing and crucial unmet medical needs of PKU patients.

The NDA for sepiapterin integrates data from the Phase 3 APHENITY trial, which has been discussed in The Lancet, along with information from the ongoing APHENITY open-label extension study. This study provides evidence of the lasting effects of sepiapterin and the patients' ability to relax dietary restrictions while maintaining control over phenylalanine (Phe) levels. Recent results from the Phe tolerance assessment indicate that around 60% of subjects achieve protein intake levels above the age-adjusted recommended daily allowance for an unaffected individual while keeping Phe levels below 360 μmol/L.

Sepiapterin, previously known as PTC923, is an oral synthetic formulation with a dual mechanism to enhance the activity of the phenylalanine hydroxylase (PAH) enzyme. Sepiapterin is rapidly absorbed and converted within cells to tetrahydrobiopterin (BH4), an essential cofactor for PAH. Additionally, it has an independent pharmacological chaperone effect, correcting PAH misfolding to improve enzyme functionality. Through these mechanisms, sepiapterin effectively lowers blood phenylalanine levels and has the potential to treat a wide array of PKU patients.

Phenylketonuria (PKU) is a rare, inherited metabolic disorder that affects brain function. It results from a defect in the gene responsible for producing the enzyme needed to break down phenylalanine. Without proper treatment or management, phenylalanine, an essential amino acid present in all proteins and most foods, can accumulate to harmful levels in the body. This can lead to severe, irreversible disabilities such as permanent intellectual disability, seizures, delayed development, memory loss, and behavioral and emotional problems. Newborns with PKU generally show no symptoms initially, but symptoms progress over time, and the damage caused by high levels of phenylalanine during the early years is irreversible. PKU is typically diagnosed through newborn screening programs. Globally, approximately 58,000 people are affected by PKU.

PTC Therapeutics, Inc. is a global biopharmaceutical company dedicated to the discovery, development, and commercialization of clinically distinct medicines that benefit both children and adults with rare disorders. PTC's innovative approach and global commercial reach underpin its investment in a diverse pipeline of transformative medications. PTC's mission is to provide access to best-in-class treatments for patients with limited treatment options. The company's strategy involves leveraging its scientific and clinical expertise and global infrastructure to deliver these therapies to patients, maximizing value for all stakeholders.