A Long-Term Study of JNT-517 in Participants With Phenylketonuria

Официальное название

An Open-Label Study to Evaluate the Long-Term Safety of JNT-517 in Participants With Phenylketonuria

Обзор

The goal of this Phase 3, open-label study is to evaluate the long-term safety of JNT-517 in pediatric and adult participants with Phenylketonuria (PKU) after completion of either Study JNT517-101 (NCT05781399) or JNT517-201 (NCT06637514) as well as participants who have not participated in a prior JNT-517 study. In this trial, all participants will receive JNT-517 using age- and weight-banded dosing as outlined in the protocol, regardless of any dose received in a previous study.

Вмешательства

• Препарат JNT-517
  JNT-517 administered orally twice daily using age- and weight-banded dosing.

Первичные конечные точки

• Number of Participants with Treatment-emergent Adverse Events (TEAEs) [Срок оценки: Screening to +2 weeks from last dose]

Вторичные конечные точки (11)

• Absolute Change from Baseline in Plasma Phe [Срок оценки: Baseline to +2 weeks from last dose]
• Percent Change from Baseline Over Time in Plasma Phe [Срок оценки: Baseline to +2 weeks from last dose]
• Percentage of Participants with Plasma Phe <600 micromoles (µM) Over Time in Participants with Baseline Phe >600 µM [Срок оценки: Baseline to +2 weeks from last dose]
• Percentage of Participants with Plasma Phe ≤360 µM Over Time in Participants with Baseline Phe >360 µM [Срок оценки: Baseline to +2 weeks from last dose]
• Percentage of Participants with Plasma Phe ≥120 µM Over Time in Participants with Baseline Phe >120 µM [Срок оценки: Baseline to +2 weeks from last dose]
• Change from Baseline Over Time in Urinary Phe and Other Amino Acids [Срок оценки: Baseline to +2 weeks from last dose]
• Absolute Change from Baseline Over Time in Dietary Phe Intake [Срок оценки: Baseline to +2 weeks from last dose]
• Absolute Change from Baseline Over Time in Dietary Intact Protein Intake (grams per kilogram per day [g/kg/day]) for Participants Achieving Plasma Phe ≤360 μM [Срок оценки: Baseline to +2 weeks from last dose]
• Percentage of Participants who Increase Phe Intake Over Time While Maintaining Plasma Phe ≤360 μM [Срок оценки: Baseline to +2 weeks from last dose]
• Absolute Change from Baseline Over Time in the Attention-Deficit/Hyperactivity Disorder Rating Scale Version 5 (ADHD-RS-5) in Pediatric Participants who Previously Participated in JNT517-301 [Срок оценки: Month 6, Month 12, and yearly thereafter up to approximately 5 years]
• Plasma Concentrations Over Time in de novo Participants Aged 4 to 11 Years [Срок оценки: Day 1 (1-hour postdose), and predose and 1-hour postdose on Day 7 and Day 14]

Критерии участия

Критерии включения

• Diagnosis of phenylketonuria (ie, PAH deficiency) by either molecular testing or biochemical criteria consistent with the applicable regional guidelines.
• Participants 4 years of age and older, inclusive, at time of Screening.
• Not on pegvaliase within 4 weeks of Screening.
• Not on sepiapterin within 2 weeks of Screening.
• If on sapropterin or large neutral amino acids at Screening, must be on a stable dose for 4 weeks prior to Screening.
• Willing and able to maintain a diet consistent in Phe content from the Screening period through the duration of the study, unless otherwise directed by a dietician as allowed in the protocol.
• Body weight ≥ 12.5 kg.
• If female of childbearing potential:

• Must have a negative serum pregnancy test at Screening and a negative urine pregnancy test by Day 1.
• Must practice sexual abstinence, or if involved in any sexual intercourse that could lead to pregnancy, must agree to use 2 different contraceptive methods, where at least 1 method must be highly effective, from Screening until at least 30 days after the last study drug administration.
• Must refrain from donating ova during the course of the study and for 30 days after the last dose of the study drug.
• Is a female not of childbearing potential or postmenopausal, defined as follows:

• Has had surgical sterilization (hysterectomy, bilateral oophorectomy, or bilateral salpingectomy).
• Has had amenorrhea for minimum of 1 year with confirmation by levels of follicle stimulating hormone testing.
• Has not achieved menarche (has not had first menstrual period). If a female achieves menarche during the study, she will need to follow the contraception requirement for females of childbearing potential.
• If male, must practice sexual abstinence, or if involved in any sexual intercourse that could lead to pregnancy, must agree to use 2 different contraceptive methods, where at least 1 method must be highly effective, from Day 1 until at least 30 days after the last study drug administration and must refrain from donating sperm during the course of the study and for 30 days after the last dose of the study drug.

Note: No restrictions are required for males who have undergone a documented vasectomy at least 4 months prior to Screening. If the vasectomy procedure is not documented or was performed less than 4 months prior to Screening, males must follow the same contraception as for non-vasectomized participants.

• Capable of giving signed informed consent, or parent/legal guardian to provide informed consent and pediatric participant to give assent, and be able to comply with study procedures.
• Participants with psychiatric illness must be well-controlled for the last 3 months prior to screening visit and, if on medication, on stable medications for the last 3 months.

Критерии исключения

• Participation in this study is not considered safe and/or feasible in the opinion of the Investigator.
• Participants have not completed a previous JNT-517 study and are eligible for another active JNT-517 trial at the site, unless approval is obtained from the medical monitor.
• Any acute or chronic medical condition that would prevent the participant from complying with the procedures or place the participant at risk if they participate in the study.
• Positive for hepatitis B or C or human immunodeficiency virus.
• Any history of significant liver disease.
• Any history of cataracts or more than minimal cataracts observed during the Screening ophthalmologic examination.
• Any surgical or medical conditions that may affect study drug absorption, distribution, metabolism, or excretion.
• Estimated glomerular filtration rate < 60 milliliters per minute per 1.73 square meters (mL/min/1.73 m\^2) by 2021 Chronic Kidney Disease Epidemiology Collaboration formula (participants aged 17 years or greater) or by Schwartz formula (participants aged 4 to 16 years of age).
• History of drug or alcohol abuse in the last year.
• Use of any medication that are inhibitors or inducers of cytochrome P450 (CYP)3A4 or inhibitors of the transporter P glycoprotein (P-gp) within 4 weeks prior to the first dose of study drug and unwilling and/or unable to avoid these medications throughout the treatment duration.
• Use of any medications that are a substrate of breast cancer resistance protein (BCRP), multidrug and toxin extrusion (MATE)1, MATE2-K, organic anion transporter 3 (OAT3), or CYP3A4 within 4 weeks prior to the first dose of study drug and unwilling and/or unable to avoid these medications throughout the treatment duration (Appendix A). CYP3A4 substrates may be allowed if reduction in exposure is not expected to impact safety of the participant after consultation with the Medical Monitor.

NOTE: Participants of childbearing potential will be permitted to continue with estrogen- or progesterone based oral contraceptives, but must agree to use 2 other methods of contraception, where at least 1 must be highly effective, or must agree to sexual abstinence during the study.

• Current, recent, or suspected infection within 2 weeks of Screening of Severe Acute Respiratory Syndrome Coronavirus 2/Coronavirus Disease 2019 (SARS-CoV-2/COVID-19).
• Unable to tolerate oral medication or inability to swallow tablets.
• Allergy to JNT-517 or any component of the investigational product.
• Any of the following laboratory values at the Screening visit:

• Alanine aminotransferase or aspartate aminotransferase values ˃ 1.5 x the upper limit of normal (ULN).
• Total bilirubin ˃ULN unless history of Gilbert Syndrome and then total bilirubin >4 milligrams per deciliter \[mg/dL\] is exclusionary.
• Hemoglobin ˂10.0 g/dL (˂100.0 grams per liter \[g/L\])
• White blood cell count ˃1 x ULN
• Platelet count ˂150 × 109/L (˂150,000/cubic millimeters\[mm\^3\])
• Participation in another investigational drug trial within 30 days (other than for JNT-517) or, if known 5 half-lives of investigational drug (whichever is longer).

Критерии приведены из реестра в оригинале (на английском). Окончательную оценку соответствия проводит исследовательский центр.

Здоровые добровольцы: Нет

Дизайн исследования

Распределение

Не применимо

Модель

Одна группа

Маскирование

Открытое

Основная цель

Лечение

Центры проведения

США · 8 центров

• University of Florida (UF) Health Shands Hospital — Gainesville
• University of South Florida — Tampa
• Oregon Health and Science University — Portland
• University of Pittsburgh Medical Center (UPMC) - Children's Hospital of Pittsburgh — Pittsburgh
• Children's Medical Center Dallas — Dallas
• University of Texas Southwestern Medical Center — Dallas
• University of Texas Health (UTHealth) Science Center at Houston — Houston
• Utah Health - The University of Utah Hospital — Salt Lake City

Австралия · 4 центра

• Children's Health Queensland - Queensland Children's Hospital — South Brisbane
• Mater Health - Mater Hospital Brisbane — South Brisbane
• Royal Adelaide Hospital — Adelaide
• Murdoch Children's Research Institute — Parkville

Идентификаторы

NCT: NCT06628128 · JNT517-501 · 359-201-00006 · 1013577 · 2025-524753-13-00

Первоисточники (государственные реестры)

• ClinicalTrials.gov (NIH, США)

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