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

Key Inclusion Criteria:

• Males and females 12 to less than 18 years of age, inclusive on Day 1.
• Clinical diagnosis of PKU.
• Ability to swallow tablets.
• Average of 2 plasma Phe levels during the Screening period greater than 360 μM and no plasma Phe level less than 300 μM.
• Body weight equal or greater than 45 kg and body mass index less than 40 kg/m2.
• Females of childbearing potential must practice sexual abstinence or agree to use 2 highly effective contraceptive methods.
• 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:

• 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 malignancy in the last 5 years, excluding nonmelanoma skin cancer.
• Any history of 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.
• Creatinine clearance less than 90 mL/min by Cockcroft-Gault formula.
• History of drug or alcohol abuse in the last year
• Current, recent, or suspected infection within 14 days of Screening of SARS CoV 2/COVID 19.
• Participation in another investigational drug trial within 30 days or, if known 5 half-lives of investigational drug (whichever is longer).
• Unable to tolerate oral medication.
• Allergy to JNT-517 or any component of the investigational product.
• 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.