New pill for PKU shows promise in small teen trial
NCT ID NCT06637514
First seen Jun 25, 2026 · Last updated Jun 27, 2026 · Updated 1 time
Summary
This study tested a new drug called JNT-517 in 14 teenagers with phenylketonuria (PKU). Participants took either JNT-517 or a placebo twice daily for 28 days. The main goal was to check safety and how the drug moves through the body, while also measuring changes in blood phenylalanine levels.
What this could mean
Our plain-language read of the trial. This is informational only, not medical advice or a prediction.
- Active substance
- JNT-517 (a tablet taken twice daily)
- What this could lead to
- If successful, this could lead to a new oral treatment option to help control phenylalanine levels in teenagers with PKU.
- What could go wrong
- This is a small, early-phase trial with only 14 participants, so results may not apply to everyone. The main goal is safety, not yet proof of effectiveness.
This is an AI summary of the original study and may miss details. Read our disclaimer.
Study facts
What this study's own registry entry says, in plain language.
- Phase
-
Phase 2
Tests whether the treatment actually works, and watches for side effects, in a larger group.
- Participants
-
14 people
The number who actually took part.
- Started
-
Jul 2025
- Finished
-
May 2026
- Lead sponsor
-
A company
The lead sponsor is a pharmaceutical, biotech, or medical-device company.
Who can take part
This study's own entry requirements. Only the study team can say for certain whether you qualify.
- Ages
-
12 to 17 years
- Sex
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Anyone
- Healthy volunteers
-
Not accepted
This study is not open to healthy volunteers. The entry requirements below say who it is open to.
Show the full entry requirements Hide the full entry requirements
Copied word for word from the study's registry entry, so the wording is the study team's rather than ours.
Key Inclusion Criteria: 1. Males and females 12 to less than 18 years of age, inclusive on Day 1. 2. Clinical diagnosis of PKU. 3. Ability to swallow tablets. 4. Average of 2 plasma Phe levels during the Screening period greater than 360 μM and no plasma Phe level less than 300 μM. 5. Body weight equal or greater than 45 kg and body mass index less than 40 kg/m2. 6. Females of childbearing potential must practice sexual abstinence or agree to use 2 highly effective contraceptive methods. 7. Capable of giving signed informed consent (emancipated minors) or parent/legal guardian to provide informed consent and the participant to give assent and confirm ability to comply with study procedures. Key Exclusion Criteria: 1. 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. 2. Positive for hepatitis B or C or human immunodeficiency virus. 3. Any history of malignancy in the last 5 years, excluding nonmelanoma skin cancer. 4. Any history of liver disease. 5. Any history of cataracts or more than minimal cataracts observed during the Screening ophthalmologic examination. 6. Any surgical or medical conditions that may affect study drug absorption, distribution, metabolism, or excretion. 7. Creatinine clearance less than 90 mL/min by Cockcroft-Gault formula. 8. History of drug or alcohol abuse in the last year 9. Current, recent, or suspected infection within 14 days of Screening of SARS CoV 2/COVID 19. 10. Participation in another investigational drug trial within 30 days or, if known 5 half-lives of investigational drug (whichever is longer). 11. Unable to tolerate oral medication. 12. Allergy to JNT-517 or any component of the investigational product. 13. Received greater than 50 mL of blood or plasma within 30 days of Screening or greater than 500 mL of blood or plasma within 60 days of Screening.
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Conditions
The condition(s) this trial relates to.
As listed by the trial registrant
The condition terms exactly as the trial's registrant entered them.
Contacts and locations
Locations
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Children's Medical Center Dallas
Dallas, Texas, 75235, United States
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Murdoch Children's Research Institute
Parkville, Melbourne, Victoria, 3052, Australia
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Oregon Health and Science University
Portland, Oregon, 97239, United States
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University of Florida (UF) Health Shands Hospital
Gainesville, Florida, 32608, United States
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University of South Florida
Tampa, Florida, 33606, United States
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University of Texas Health (UTHealth) Science Center at Houston
Houston, Texas, 77030, United States
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Utah Health - The University of Utah Hospital
Salt Lake City, Utah, 84112, United States
More trials for these conditions
Other studies related to the condition(s) this trial covers.
- Can weekly Finger-Prick tests improve PKU control?
- Hidden weight problem: PKU adults face higher obesity risk, scientists investigate why
- New oral drug aims to tame PKU's toxic protein buildup
- Experimental enzyme injection aims to tame PKU's toxic amino acid
- Tiny tablets could make PKU management easier for patients
- New PKU drug JNT-517 moves to Long-Term safety trial