First-in-Human, Multiple Part Clinical Study of JNT-517 in Healthy Participants and in Participants With Phenylketonuria

Study Identifier:
JNT517-101
ClinicalTrials.gov Identifier:
NCT05781399
EudraCT Identifier:
N/A
EU CT ID:
N/A
Sponsor:
Otsuka Pharmaceutical Development & Commercialization, Inc.
Study Contact Information:
N/A
Active, Not Recruiting
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Study Details

Medical Condition
  • Phenylketonuria (PKU)
Study Drug
  • Drug: JNT-517 Suspension
  • Drug: Placebo Suspension
  • Drug: JNT-517 Tablet
  • Drug: Placebo Tablet
Date
Oct 2022 - Sep 2025
Phase 1/2
Phase 2/3
Phase 1
Phase 2
Phase 3
Phase 4
N/A
Patient Requirements
Sex: Female & Male
Age: 18 - 65 Years
Requirements Information
Inclusion and Exclusion Criteria
Inclusion Criteria
  • Parts A, B, C, and F:
  • Males and females 18 to 55 years of age.
  • Medically healthy with no clinically significant medical history.
  • Body mass index (BMI) of 18-40 kg/m2 and total body weight \>50 kg (110 lbs).
  • Non-smoker for at least 2 weeks prior to dosing and willing to abstain during the study.
  • Part D and E:
  • Males and females 18 to 65 years of age, inclusive.
  • Diagnosis of PKU with a confirmed genotype.
  • At least 2 plasma Phe levels \>600 μM over the past 12 months.
  • BMI of 18-40 kg/m2.
  • All Parts:
  • Females of childbearing potential must agree to use 2 highly effective contraceptive methods.
  • Capable of giving signed informed consent and able to comply with study procedures.
Exclusion Criteria
  • All Parts:
  • 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 non-melanoma skin cancer.
  • Any history of liver disease.
  • Any surgical or medical conditions that may affect study drug absorption, distribution, metabolism, or excretion.
  • Participation in another investigational drug trial within 30 days or, if known, 5 half-lives of the investigational drug (whichever is longer).
  • History of drug/alcohol abuse in the last year.
  • Current, recent, or suspected infection within 4 weeks of Screening of SARS-CoV-2/COVID-19.
  • Received a vaccine for SARS-CoV-2/COVID-19 within 14 days of Screening.
  • Unable to tolerate oral medication.
  • Allergy to JNT-517 or any component of the investigational product.
  • Received \>50 mL of blood or plasma within 30 days of Screening or \>500 mL of blood or plasma within 60 days of Screening.

Protocol Summary

The goal of Parts A and B of this Phase 1/2, first-in-human, randomized study is to assess the safety, tolerability, and pharmacokinetics (PK) of single (SAD) and multiple (MAD) ascending doses of oral JNT-517 in healthy participants. In Part C, the goal is to evaluate the differences in bioavailability between a tablet and suspension formulation of JNT-517 and the food effect in healthy volunteers. All participants in Part C will receive JNT-517. The goal of Part D is to assess the safety, tolerability, PK, and effect on urinary Phe and other amino acids of JNT-517 in participants with phenylketonuria (PKU). Participants in Part D will receive either JNT-517 or placebo and will be blinded to their treatment assignment.

The study consists of 6 parts:

  • Part A: SAD in healthy participants -randomized, double-blind, placebo-controlled
  • Part B: MAD in healthy participants (14 days)-randomized, double-blind, placebo-controlled
  • Part C: Relative bioavailability of 2 formulations and food effect in healthy participants-randomized, open-label
  • Part D: Phase 2 in participants with PKU (4 weeks)-randomized, double-blind, placebo-controlled
  • Part E: Phase 2 in participants with PKU (4 weeks) open label
  • Part F: SAD Phase 1 in healthy participants, randomized, double-blind, placebo-controlled

In each part, participants will complete a Screening Period, a Treatment Period, and a Follow-up Period for safety.

Study Locations

Location
Status
Location
University of Florida College of Medicine
Gainesville, Florida, United States, 32610
Status
N/A
Location
University of South Florida
Tampa, Florida, United States, 33620
Status
N/A
Location
Rare Disease Research
Atlanta, Georgia, United States, 30329
Status
N/A
Location
Ann & Robert H. Lurie Children's Hospital of Chicago
Chicago, Illinois, United States, 60611
Status
N/A
Location
University of Nebraska Medical Center
Omaha, Nebraska, United States, 68198
Status
N/A
Location
Oregon Health & Sciences University
Portland, Oregon, United States, 97239
Status
N/A
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© 2025 Otsuka America Pharmaceutical,
Inc All rights reserved.

July 2025 01US25EUC0279

Requirements information
Inclusion criteria
  • Parts A, B, C, and F:
  • Males and females 18 to 55 years of age.
  • Medically healthy with no clinically significant medical history.
  • Body mass index (BMI) of 18-40 kg/m2 and total body weight \>50 kg (110 lbs).
  • Non-smoker for at least 2 weeks prior to dosing and willing to abstain during the study.
  • Part D and E:
  • Males and females 18 to 65 years of age, inclusive.
  • Diagnosis of PKU with a confirmed genotype.
  • At least 2 plasma Phe levels \>600 μM over the past 12 months.
  • BMI of 18-40 kg/m2.
  • All Parts:
  • Females of childbearing potential must agree to use 2 highly effective contraceptive methods.
  • Capable of giving signed informed consent and able to comply with study procedures.
Exclusion criteria
  • All Parts:
  • 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 non-melanoma skin cancer.
  • Any history of liver disease.
  • Any surgical or medical conditions that may affect study drug absorption, distribution, metabolism, or excretion.
  • Participation in another investigational drug trial within 30 days or, if known, 5 half-lives of the investigational drug (whichever is longer).
  • History of drug/alcohol abuse in the last year.
  • Current, recent, or suspected infection within 4 weeks of Screening of SARS-CoV-2/COVID-19.
  • Received a vaccine for SARS-CoV-2/COVID-19 within 14 days of Screening.
  • Unable to tolerate oral medication.
  • Allergy to JNT-517 or any component of the investigational product.
  • Received \>50 mL of blood or plasma within 30 days of Screening or \>500 mL of blood or plasma within 60 days of Screening.

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