A Study of JNT-517 in Participants With Phenylketonuria (PKU) (NCT06971731) | Clinical Trial Compass
RecruitingPhase 3
A Study of JNT-517 in Participants With Phenylketonuria (PKU)
United States120 participantsStarted 2025-10-20
Plain-language summary
The goal of this Phase 3, randomized study is to assess the safety, efficacy, tolerability, and pharmacokinetics (PK) of oral JNT-517 in adults (18 years of age or older) with PKU. Participants will receive either JNT-517 or placebo and will be blinded to their treatment assignment. Participants will have a 2 in 3 (or approximately 67%) chance of receiving JNT-517 during the first part of the study which will last approximately six weeks. During the second part of the study every participant who continues in the study will receive one of two doses of JNT-517 for an additional 46 weeks. The study requires a screening period of up to 35 days to ensure dietary stabilization and amino acid levels required to meet study eligibility. In total, participation in the study could last for up to 400 days.
Participants will:
Take 75 mg JNT-517 or 150 mg JNT-517, or a placebo BID (2x per day) for approximately 365 days; Visit the clinic or have a mobile health nurse visit your home for checkups and tests; Collect urine sample at home and bring to clinic on specified days; Keep a food diary 3 days before each study visit
Who can participate
Age range18 Years
SexALL
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AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion criteria
✓. Males and females ≥18 years of age on Day 1
✓. Clinical diagnosis of PKU
✓. Average of at least 3 plasma Phe levels (after \>4-hour fast) during Screening period of ≥360 μmol/L
✓. Not on pegvaliase within 4 weeks prior to Screening
✓. If on sapropterin or large neutral amino acids, such as PheBloc®, NeoPhe®, and PreKunil® at Screening, must be on a stable dose 4 weeks prior to Screening and for the entire study duration.
✓. Willing and able to maintain a stable diet in Phe and total protein (intact protein and medical food protein) and able to adjust diet through the duration of the study according to the Dietary Management Guidelines
✓. Body weight \>40 kilograms (kg)
✓. If biologically female of childbearing potential:
Exclusion criteria
✕. Any acute or uncontrolled 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
What they're measuring
1
Absolute Change in Plasma Phenylalanine (Phe) From Baseline to the Mean of Weeks 2, 4, and 6 in the JNT-517 150 mg BID Dose Group at End of Period 1
Timeframe: Baseline to End of Period 1 (Week 6)
Trial details
NCT IDNCT06971731
SponsorOtsuka Pharmaceutical Development & Commercialization, Inc.
✕. Positive for hepatitis B or C or human immunodeficiency virus
✕. Any history of malignancy of any organ system (other than non-melanoma skin cancer or in situ cervical cancer), treated or untreated, within the past 5 years, regardless of whether there is evidence of local recurrence or metastases
✕. Any history of significant liver disease
✕. Any history of cataracts or more than minimal cataracts observed during the Screening ophthalmologic examination. Minimal cataracts are defined as changes similar to lens opacities classification system III (LOCS III), lens grade C1, N1 or P1
✕. Any surgical or medical conditions that may affect study drug absorption, distribution, metabolism, or excretion
✕. Estimated glomerular filtration rate (eGFR) \<60 mL/min/1.73 m2 by 2021 Chronic Kidney Disease Epidemiology Collaboration formula
✕. Participation in another investigational drug trial within 30 days or, if known, 5 half-lives of the investigational drug (whichever is longer). For gene therapy or editing trials, participants must have received the intervention \>6 months prior to Screening visit and with stable plasma Phe in the past 2 months prior to Screening visit.