PTC Therapeutics Presents New Sepiapterin Data from Ongoing Studies
PTC Therapeutics (NASDAQ: PTCT) has presented new data from their Phase 3 APHENITY trial and open-label extension study for sepiapterin treatment in phenylketonuria (PKU) patients at the 2025 ACMG Annual Meeting.
Key findings demonstrate that 97% of participants in the Phe tolerance protocol showed improved dietary flexibility, with a mean increase of 126% in protein intake. Notably, 66% of subjects reached or exceeded the age-adjusted recommended daily protein intake while maintaining blood Phe control.
The genetic variant analysis revealed that over 70% of study participants had a Genotype-Phenotype Value consistent with classical PKU. The results suggest significant treatment benefits, including for patients with mutations not responsive to BH4 and those with classical disease phenotype.
PTC Therapeutics (NASDAQ: PTCT) ha presentato nuovi dati dal loro studio di Fase 3 APHENITY e dallo studio di estensione in aperto per il trattamento con sepiapterin nei pazienti affetti da fenilchetonuria (PKU) durante il Congresso Annuale ACMG 2025.
I risultati chiave dimostrano che il 97% dei partecipanti nel protocollo di tolleranza alla Phe ha mostrato una maggiore flessibilità dietetica, con un aumento medio del 126% nell'assunzione di proteine. È importante notare che il 66% dei soggetti ha raggiunto o superato l'assunzione giornaliera raccomandata di proteine, adeguata all'età, mantenendo il controllo dei livelli di Phe nel sangue.
L'analisi delle varianti genetiche ha rivelato che oltre il 70% dei partecipanti allo studio presentava un valore Genotipo-Fenotipo coerente con la PKU classica. I risultati suggeriscono significativi benefici terapeutici, inclusi quelli per i pazienti con mutazioni non responsivi al BH4 e quelli con fenotipo di malattia classica.
PTC Therapeutics (NASDAQ: PTCT) ha presentado nuevos datos de su ensayo de Fase 3 APHENITY y del estudio de extensión abierto para el tratamiento con sepiapterina en pacientes con fenilcetonuria (PKU) en la Reunión Anual ACMG 2025.
Los hallazgos clave demuestran que el 97% de los participantes en el protocolo de tolerancia a la Phe mostraron una mayor flexibilidad dietética, con un aumento medio del 126% en la ingesta de proteínas. Cabe destacar que el 66% de los sujetos alcanzaron o superaron la ingesta diaria recomendada de proteínas ajustada por edad, manteniendo el control de Phe en sangre.
El análisis de variantes genéticas reveló que más del 70% de los participantes del estudio tenían un Valor Genotipo-Fenotipo consistente con la PKU clásica. Los resultados sugieren beneficios significativos del tratamiento, incluidos aquellos para pacientes con mutaciones no responsables al BH4 y aquellos con fenotipo de enfermedad clásica.
PTC Therapeutics (NASDAQ: PTCT)는 2025 ACMG 연례 회의에서 페닐케톤뇨증(PKU) 환자에 대한 세피아프테린 치료를 위한 3상 APHENITY 시험과 공개 라벨 확장 연구의 새로운 데이터를 발표했습니다.
주요 발견에 따르면 97%의 참가자가 Phe 내성 프로토콜에서 식이 유연성이 향상되었으며, 단백질 섭취량이 평균 126% 증가했습니다. 특히, 66%의 피험자가 연령 조정 권장 일일 단백질 섭취량에 도달하거나 이를 초과하면서 혈중 Phe 수치를 조절했습니다.
유전적 변이 분석 결과 70% 이상의 연구 참가자가 고전적 PKU와 일치하는 유전자형-표현형 값을 가지고 있음을 밝혔습니다. 결과는 BH4에 반응하지 않는 돌연변이가 있는 환자와 고전적 질병 표현형을 가진 환자에게도 상당한 치료 혜택이 있음을 시사합니다.
PTC Therapeutics (NASDAQ: PTCT) a présenté de nouvelles données de son essai de phase 3 APHENITY et de l'étude d'extension ouverte pour le traitement par sépiaphtérine chez des patients atteints de phénylcétonurie (PKU) lors de la réunion annuelle ACMG 2025.
Les résultats clés montrent que 97 % des participants au protocole de tolérance à la Phe ont montré une flexibilité alimentaire améliorée, avec une augmentation moyenne de 126 % de l'apport en protéines. Notamment, 66 % des sujets ont atteint ou dépassé l'apport quotidien recommandé en protéines ajusté à l'âge tout en maintenant le contrôle du Phe dans le sang.
L'analyse des variants génétiques a révélé que plus de 70 % des participants à l'étude avaient une valeur génotype-phénotype cohérente avec la PKU classique. Les résultats suggèrent des avantages thérapeutiques significatifs, y compris pour les patients présentant des mutations non réactives au BH4 et ceux ayant un phénotype de maladie classique.
PTC Therapeutics (NASDAQ: PTCT) hat auf dem ACMG-Jahrestreffen 2025 neue Daten aus ihrer Phase-3-Studie APHENITY und der offenen Verlängerungsstudie zur Behandlung mit Sepiapterin bei Patienten mit Phenylketonurie (PKU) vorgestellt.
Wichtige Ergebnisse zeigen, dass 97% der Teilnehmer im Phe-Toleranzprotokoll eine verbesserte diätetische Flexibilität aufwiesen, mit einem mittleren Anstieg von 126% bei der Proteinzufuhr. Bemerkenswert ist, dass 66% der Probanden die altersangepasste empfohlene tägliche Proteinzufuhr erreichten oder überschritten und gleichzeitig die Blut-Phe-Kontrolle aufrechterhielten.
Die Analyse genetischer Varianten ergab, dass über 70% der Studienteilnehmer einen Genotyp-Phänotyp-Wert hatten, der mit klassischer PKU übereinstimmte. Die Ergebnisse deuten auf erhebliche Behandlungsvorteile hin, auch für Patienten mit Mutationen, die nicht auf BH4 ansprechen, und für solche mit klassischem Krankheitsphänotyp.
- 97% success rate in improving dietary flexibility for PKU patients
- 126% mean increase in protein intake while maintaining Phe control
- Effective in classical PKU patients with non-BH4 responsive genotypes
- 66% of patients reached normal protein intake recommendations
- None.
Insights
PTC Therapeutics has released compelling new data from their Phase 3 APHENITY trial for sepiapterin in phenylketonuria (PKU), a rare genetic disorder where patients cannot properly metabolize the amino acid phenylalanine. Without effective treatment, PKU patients must follow extremely restrictive low-protein diets to prevent phenylalanine buildup that can cause neurological damage.
The results demonstrate significant clinical benefits, particularly regarding diet liberalization – arguably the most meaningful outcome for patients' quality of life.
What makes these findings particularly significant is the efficacy demonstrated in patients with classical PKU (over
These results suggest sepiapterin could address a substantial unmet need across the PKU spectrum, including the most challenging-to-treat patient segments. While the drug still requires regulatory approval, these data strengthen its clinical profile and commercial potential in a condition where few effective therapies exist for severe patients.
The interim results from PTC Therapeutics' APHENITY extension study represent a potentially significant advancement in PKU management. The
Most notably, the genetic variant analysis reveals efficacy in patients with classical PKU genotypes not responsive to BH4 supplementation. This population has been particularly challenging to treat, as they typically have minimal residual phenylalanine hydroxylase enzyme activity. The current standard treatment (sapropterin/Kuvan) primarily benefits those with residual enzyme function, leaving those with classical PKU dependent on highly restrictive diets and medical formula.
The fact that
Sepiapterin appears to be working through a mechanism that bypasses the genetic defects in the phenylalanine hydroxylase enzyme pathway, potentially explaining its broader efficacy across genotypes. If these results are maintained in the completed study and lead to regulatory approval, sepiapterin could represent a paradigm shift in PKU management, particularly for patients with classical disease who have had therapeutic options.
— Results show
their dietary Phe intake with a mean increase of
— Genetic variant analysis of Phase 3 APHENITY trial demonstrates meaningful effect in
classical subjects with non-BH4 responsive genotypes —
Key data presented include:
- Over
97% of subjects participating in the Phe tolerance protocol of the APHENITY open-label extension study demonstrate the ability to liberalize their diet while on sepiapterin treatment, with a mean increase in protein intake of126% 66% of subjects participating in the Phe tolerance sub study reached or exceeded the age-adjusted recommended daily allowance of protein intake for an individual without PKU, while maintaining control of blood Phe levels- Genetic variant analysis of subjects participating in the APHENITY study demonstrates that over
70% had a Genotype-Phenotype Value (GPV) consistent with classical PKU
"These new data provide further evidence of the meaningful benefit sepiapterin can provide for children and adults with PKU, including those with the most severe form of the disease," said Matthew B. Klein, M.D., Chief Executive Officer of PTC Therapeutics. "Furthermore, the treatment benefit demonstrated in individuals with mutations not responsive to BH4 and consistent with classical disease phenotype support the potential to penetrate all key patient segments."
The data were presented in a poster titled "Interim Results From the APHENITY Extension Study: Sepiapterin Reduces Blood Phe with Improved Dietary Phe Tolerance in Participants With Phenylketonuria" and in a symposium presented by Nicola Longo, M.D., Ph.D., Professor and Chief of Division of Clinical Genetics at the University of
About Sepiapterin
Sepiapterin (formerly PTC923), an oral formulation of synthetic sepiapterin, has a dual mechanism of action to increase activity of the phenylalanine hydroxylase (PAH) enzyme. First, sepiapterin is a precursor compound that is rapidly absorbed and converted intracellularly to tetrahydrobiopterin (BH4), a critical cofactor of PAH. Sepiapterin also has an independent pharmacological chaperone effect, correcting PAH misfolding to enhance the enzyme function. Through this dual mechanism of action, sepiapterin effectively reduces blood phenylalanine (Phe) levels and has the potential to treat a broad range of PKU patients.
About Phenylketonuria
Phenylketonuria (PKU) is a rare, inherited metabolic disease, which affects the brain. It is caused by a defect in the gene that helps create the enzyme needed to break down phenylalanine. If left untreated or poorly managed, phenylalanine – an essential amino acid found in all proteins and most foods – can build up to harmful levels in the body. This causes severe and irreversible disabilities, such as permanent intellectual disability, seizures, delayed development, memory loss, and behavioral and emotional problems. Newborns with phenylketonuria initially don't have any symptoms, but symptoms are usually progressive, and damage caused by toxic levels of phenylalanine in the first few years of life is irreversible. Diagnosis of phenylketonuria usually takes place during newborn screening programs. There are an estimated 58,000 people with phenylketonuria globally.
About PTC Therapeutics, Inc.
PTC is a global biopharmaceutical company focused on the discovery, development and commercialization of clinically differentiated medicines that provide benefits to children and adults living with rare disorders. PTC's ability to globally commercialize products is the foundation that drives investment in a robust and diversified pipeline of transformative medicines and our mission to provide access to best-in-class treatments for patients who have an unmet medical need. The company's strategy is to leverage its strong scientific expertise and global commercial infrastructure to maximize value for its patients and other stakeholders. To learn more about PTC, please visit us at www.ptcbio.com and follow us on Facebook, X, and LinkedIn.
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As with any pharmaceutical under development, there are significant risks in the development, regulatory approval and commercialization of new products. There are no guarantees that any product will receive or maintain regulatory approval in any territory, or prove to be commercially successful, including sepiapterin.
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SOURCE PTC Therapeutics, Inc.
FAQ
What are the key results from PTC Therapeutics' APHENITY trial for PKU treatment?
How effective is sepiapterin for classical PKU patients with PTCT's treatment?
What percentage of patients improved their diet flexibility in PTCT's PKU study?
What is the average protein intake increase achieved in PTCT's sepiapterin trial?
