Evaluating sepiapterin for children with phenylketonuria

Is this trial a fit for you?

A plain-English reading of the study's rules. Only the study team can confirm whether you qualify.

What this trial studies

This trial aims to assess the long-term effectiveness of sepiapterin in preserving neurocognitive function in children diagnosed with phenylketonuria (PKU). The study is divided into two parts: the first part involves an open-label test to determine responsiveness to sepiapterin, while the second part consists of an open-label treatment phase. Participants will be monitored for their blood phenylalanine levels and overall cognitive development throughout the study.

Why it matters

Who can join: the full rules

Key Inclusion Criteria:

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.

For participants ≥1 month of age at Screening:

* 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.
* A minimum of 1 documented blood Phe measurement \<480 μmol/L within 1 month prior to 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.

Key Exclusion Criteria:

* History of allergies or adverse reactions to any of the ingredients or excipients of synthetic tetrahydrobiopterin (BH4) or sepiapterin.
* Serious neuropsychiatric illness (for example, major depression) not currently under medical control or other concurrent disease or condition that, in the opinion of the investigator or sponsor, would interfere with the participant's ability to participate in the study or increase the risk of participation for that participant.
* Treatment with BH4 supplementation (sapropterin, Kuvan®) within 3 months prior to Screening.
* Current participation in another investigational drug study or use of any investigational agent within 30 days prior to Screening.
* Confirmed diagnosis of a primary BH4 deficiency as evidenced by biallelic pathogenic mutations in 6-pyruvoyltetrahydropterin synthase, recessive Guanosine-5'-triphosphate (GTP) cyclohydrolase I, sepiapterin reductase, quinoid dihydropteridine reductase, or pterin 4-alphacarbinolamine dehydratase genes.
* Any clinically significant laboratory abnormality as determined by the investigator.
* Any past medical history of an abnormal physical examination and/or laboratory findings indicative of signs or symptoms of renal disease, including calculated (Bedside Schwartz Equation) glomerular filtration rate (GFR) \<60 milliliters (mL)/minute (min)/1.73 square meter (m\^2).
* Major surgery within 90 days prior to Screening visit.
* Previous treatment for \>6 weeks with sepiapterin (that is, Sephience).

Note: Other protocol-defined inclusion and exclusion criteria may apply.

Where it's running

• Indiana University School of Medicine
  Indianapolis, Indiana, United States Recruiting
• Perth Children's Hospital
  Nedlands, Australia Recruiting
• Women and Children Hospital
  North Adelaide, Australia Recruiting
• The Royal Children's Hospital
  Parkville, Australia Recruiting
• Children's Health Queensland -Queenslan Children Hospital
  South Brisbane, Australia Recruiting
• Centre Hospitalier Universitaire (CHU) de Lille - Hôpital Jeanne de Flandre
  Lille, France Recruiting

Study contacts

• Study coordinator: Patient Advocacy
• Email: medinfo@ptcbio.com
• Phone: 1-866-562-4620

Similar studies

Other studies for the same condition or treatment. Recruiting studies are listed first.

• Impact of a Phenylalanine-Restricted Diet on Gut Health in Children with PKU

  This study looks at how a Phe-restricted diet, with or without sapropterin or sepiapterin, might affect gut health in kids with PKU.

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• How Repinatrabit is processed in adults with liver or kidney impairment versus normal function

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• Eating disorders in people with phenylketonuria

  This study looks at whether eating disorders and BMI issues are more common in people with phenylketonuria who are followed at a French hospital.

  Recruiting Central Hospital, Nancy, France · Nancy · NCT07698743

• GenSci144 tablets early-dose study for phenylketonuria treatment

  This early-phase trial tests a single dose of GenSci144 tablets in healthy adults to see if it is safe and tolerable, while also looking at how the body processes the drug.

  Recruiting Phase 1 Changchun GeneScience Pharmaceutical Co., Ltd. · Jinan, Shandong · NCT07685210

• Immune Modulation During Palynziq Treatment in Adults

  This study tests whether adding low-dose methotrexate can help people with PKU tolerate Palynziq better and achieve better blood levels of phenylalanine.

  Recruiting at 10 sites Phase 4 BioMarin Pharmaceutical · Los Angeles, California and 11 other locations · NCT07477691

• AG-181 safety and tolerability in people with phenylketonuria

  This trial will test AG-181 for safety and tolerability in people with PKU who have high blood phenylalanine and at least one R408W PAH mutation.

  Recruiting at 5 sites Phase 1 Agios Pharmaceuticals, Inc. · Indianapolis, Indiana and 4 other locations · NCT07241234

How to take part

1. Review the eligibility criteria above with your treating physician.
2. Check the official listing on ClinicalTrials.gov for the latest contact details and recruitment status.
3. Contact the study coordinator or principal investigator to ask for pre-screening. Pre-screening is free and never obligates you to enroll.