Actively Recruiting
A Long-Term Study of JNT-517 in Participants With Phenylketonuria
Led by Otsuka Pharmaceutical Development & Commercialization, Inc. · Updated on 2026-05-01
240
Participants Needed
12
Research Sites
129 weeks
Total Duration
On this page
AI-Summary
What this Trial Is About
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.
CONDITIONS
Official Title
A Long-Term Study of JNT-517 in Participants With Phenylketonuria
Who Can Participate
Eligibility Criteria
You may qualify if you...
- Diagnosis of phenylketonuria (PAH deficiency) confirmed by molecular or biochemical testing
- Participants aged 4 years and older at screening
- Not taking pegvaliase within 4 weeks before screening
- Not taking sepiapterin within 2 weeks before screening
- Stable dose of sapropterin or large neutral amino acids for 4 weeks prior to screening if applicable
- Willing and able to maintain a consistent phenylalanine diet throughout the study
- Body weight of at least 12.5 kg
- For females of childbearing potential: negative pregnancy tests at screening and Day 1; agree to use two contraceptive methods or sexual abstinence from screening until 30 days after last dose; no ova donation during study and for 30 days after last dose
- Females not of childbearing potential or postmenopausal defined by surgical sterilization, amenorrhea for at least 1 year with hormone confirmation, or pre-menarche status
- Males must practice sexual abstinence or use two contraceptive methods from Day 1 until 30 days after last dose, and refrain from sperm donation during this period; exception for documented vasectomy at least 4 months prior
- Able to provide informed consent (or parent/guardian consent and pediatric assent) and comply with study procedures
- Psychiatric illness must be well-controlled for 3 months prior to screening with stable medications if applicable
You will not qualify if you...
- Investigator determines participation is unsafe or not feasible
- Participants who have not completed a previous JNT-517 study and are eligible for another active JNT-517 trial unless approved
- Acute or chronic medical conditions preventing compliance or increasing risk
- Positive for hepatitis B, hepatitis C, or HIV
- History of significant liver disease
- History of cataracts or more than minimal cataracts on screening eye exam
- Surgical or medical conditions affecting drug absorption, distribution, metabolism, or excretion
- Estimated glomerular filtration rate (eGFR) less than 60 mL/min/1.73 m2 for adults or children
- History of drug or alcohol abuse in the past year
- Use of CYP3A4 or P-gp inhibitors/inducers within 4 weeks prior to first dose and unwilling/unable to avoid during study
- Use of substrates of BCRP, MATE1, MATE2-K, OAT3, or CYP3A4 within 4 weeks prior to first dose and unwilling/unable to avoid during study
- Current, recent, or suspected COVID-19 infection within 2 weeks of screening
- Unable to tolerate oral medication or swallow tablets
- Allergy to JNT-517 or any component of the drug
- Specific abnormal lab values at screening including elevated liver enzymes, bilirubin, low hemoglobin, high white blood cell count, or low platelets
- Participation in another investigational drug trial within 30 days prior to enrollment (except JNT-517) or within 5 half-lives of the drug, whichever is longer
AI-Screening
AI-Powered Screening
Complete this quick 3-step screening to check your eligibility
Trial Site Locations
Total: 12 locations
1
University of Florida (UF) Health Shands Hospital
Gainesville, Florida, United States, 32608
Actively Recruiting
2
University of South Florida
Tampa, Florida, United States, 33606
Actively Recruiting
3
Oregon Health and Science University
Portland, Oregon, United States, 97239
Actively Recruiting
4
University of Pittsburgh Medical Center (UPMC) - Children's Hospital of Pittsburgh
Pittsburgh, Pennsylvania, United States, 15224
Actively Recruiting
5
Children's Medical Center Dallas
Dallas, Texas, United States, 75235
Actively Recruiting
6
University of Texas Southwestern Medical Center
Dallas, Texas, United States, 75390
Actively Recruiting
7
University of Texas Health (UTHealth) Science Center at Houston
Houston, Texas, United States, 77030
Actively Recruiting
8
Utah Health - The University of Utah Hospital
Salt Lake City, Utah, United States, 84112
Actively Recruiting
9
Children's Health Queensland - Queensland Children's Hospital
South Brisbane, Queensland, Australia, 4101
Actively Recruiting
10
Mater Health - Mater Hospital Brisbane
South Brisbane, Queensland, Australia, 4101
Actively Recruiting
11
Royal Adelaide Hospital
Adelaide, South Australia, Australia, 5000
Actively Recruiting
12
Murdoch Children's Research Institute
Parkville, Victoria, Australia, 3052
Actively Recruiting
Research Team
O
Otsuka Call Center
CONTACT
How is the study designed?
Study Type
INTERVENTIONAL
Masking
NONE
Allocation
NA
Model
SINGLE_GROUP
Primary Purpose
TREATMENT
Number of Arms
1
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