A Phase 2 Study of JNT-517 in Adolescent Participants With Phenylketonuria

Phase 2

Not yet recruiting

• Conditions: Phenylketonuria (PKU)
• Interventions: Drug: JNT-517 Tablet; Other: Placebo

• Registration Number: NCT06637514
• Lead Sponsor: Jnana Therapeutics

Brief Summary

The goal of this Phase 2, randomized study is to assess the safety, tolerability, and pharmacokinetics (PK) of oral JNT-517 in adolescents (12 to less than 18 years of age) with PKU. Participants will receive either JNT-517 or placebo and will be blinded to their treatment assignment. Participants will have a 4 in 5 (or 80%) chance of receiving JNT-517. The study will last for up to 63 days including a Screening period, Treatment period and Follow-up period for safety.

Participants will:

* Take 75 mg JNT-517 or a placebo BID (2x per day) for 28 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

Detailed Description

Not available

Study Timeline

• Study First Submitted: 2024-10-07
• Study First Submitted QC: 2024-10-09
• Study First Posted: 2024-10-15
• Status Verified: 2025-05
• Last Update Submitted: 2025-05-07
• Last Update Posted: 2025-05-11
• Study Start: 2025-07
• Primary Completion: 2025-12
• Study Completion: 2026-02

Recruitment & Eligibility

• Status: NOT_YET_RECRUITING
• Sex: All
• Target Recruitment: 10

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.

Study & Design

• Study Type: INTERVENTIONAL
• Study Design: PARALLEL

Arm && Interventions

Group	Intervention	Description
JNT-517 - 75 mg BID	JNT-517 Tablet	Drug: JNT-517 Tablet
Placebo - BID	Placebo	Drug: Placebo Tablet
JNT-517 - 150 mg BID	JNT-517 Tablet	Drug: JNT-517 Tablet - 150 mg BID is a potential dose that may be used in the study. After safety, efficacy and pharmacokinetic data (PK) data have been reviewed for the first 5 participants assigned in the study, a decision will be made to increase dosage for additional participants.

Primary Outcome Measures

Name	Time	Method
Number of participants with treatment-emergent adverse events (TEAEs)	Screening to Study Completion (Average of 9 weeks)	Reported based on results of 12-lead electrocardiograms (ECGs), vital signs and clinical laboratory tests.

Secondary Outcome Measures

Name	Time	Method
Plasma AUC (area under the concentration-time curve)	Screening to Study Completion (Average of 9 weeks)
Cmax (maximum observed concentration)	Screening to Study Completion (Average of 9 weeks)
Tmax (time to Cmax)	Screening to Study Completion (Average of 9 weeks)
Change over time in plasma phenylalanine (Phe) and other amino acids	Screening to Study Completion (Average of 9 weeks)
Change over time in urinary phenylalanine (Phe) and other amino acids	Screening to Study Completion (Average of 9 weeks)