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A Long-Term Safety Study of PTC923 in Participants With Phenylketonuria

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details.
 
ClinicalTrials.gov Identifier: NCT05166161
Recruitment Status : Recruiting
First Posted : December 21, 2021
Last Update Posted : April 9, 2024
Sponsor:
Information provided by (Responsible Party):
PTC Therapeutics

Tracking Information
First Submitted Date  ICMJE December 8, 2021
First Posted Date  ICMJE December 21, 2021
Last Update Posted Date April 9, 2024
Actual Study Start Date  ICMJE February 14, 2022
Estimated Primary Completion Date February 7, 2025   (Final data collection date for primary outcome measure)
Current Primary Outcome Measures  ICMJE
 (submitted: March 27, 2023)
  • Number of Treatment-Emergent Adverse Events (TEAEs) [ Time Frame: Baseline up to end of study (up to approximately 2.5 years) ]
    A TEAE is any unfavorable or unintended sign (including an abnormal laboratory finding), symptom or disease in a study participant who is administered study drug in this study
  • Change From Baseline in Dietary Phe/Protein Consumption at Week 26, Measured During Phe Tolerance Assessment Period [ Time Frame: Baseline, Week 26 ]
    Phe tolerance is defined as the total amount of dietary Phe (milligrams [mg]/kilogram [kg] per day) ingested while maintaining blood Phe levels within the range of 40 to 360 micromoles (μmol)/liter (L) (defined as ≥40 to <360 μmol/L).
Original Primary Outcome Measures  ICMJE
 (submitted: December 8, 2021)
  • Number of Treatment-Emergent Adverse Events (TEAEs) [ Time Frame: Baseline up to end of study (up to approximately 2.5 years) ]
  • Change From Baseline in Dietary Phe/Protein Consumption at Week 26, Measured During Phe Tolerance Assessment Period [ Time Frame: Baseline, Week 26 ]
    Phe tolerance is defined as the total amount of dietary Phe (mg/kg per day) ingested while maintaining blood Phe levels within the range of 40 to 360 micromoles (μmol)/liter (L) (defined as ≥40 to <360 μmol/L).
Change History
Current Secondary Outcome Measures  ICMJE
 (submitted: March 27, 2023)
  • Change From Baseline in Quality of Life (QOL) Using Phenylketonuria-Quality of Life (PKU-QOL) Questionnaire at Months 8, 14, 20, 26, 32, and 38 [ Time Frame: Baseline, Months 8, 14, 20, 26, 32, and 38 ]
    QOL using PKU-QOL questionnaire will be assessed in the subset of participants who are able to complete the PKU-QOL (that is, participants whose primary language is English [British or American], Turkish, Dutch, German, Spanish, Italian, Portuguese, or French) (ages 6 to 8 years Parent PKU-QOL; ages 9 to 11 years Child PKU-QOL; ages 12 to 17 years Adolescent PKU-QOL; ages ≥18 years Adult PKU-QOL).
  • Change From Baseline in QOL Using the European Quality of Life - 5 Dimensions (EQ-5D) at Months 8, 14, 20, 26, 32, and 38 [ Time Frame: Baseline, Months 8, 14, 20, 26, 32, and 38 ]
    QOL will be assessed using the EQ-5D (EQ-5D-Y Proxy Version 1 [3 to 7 years]; EQ-5D-Y [8 to 15 years]; EQ-5D-5L ([≥16 years]).
Original Secondary Outcome Measures  ICMJE
 (submitted: December 8, 2021)
  • Change From Baseline in Quality of Life (QOL) Using Phenylketonuria-Quality of Life (PKU-QOL) Questionnaire at Months 8, 14, 20, 26, 32, and 38 [ Time Frame: Baseline, Months 8, 14, 20, 26, 32, and 38 ]
    QOL using PKU-QOL questionnaire will be assessed in the subset of participants that are able to complete the PKU-QOL (that is, participants whose primary language is English [British or American], Turkish, Dutch, German, Spanish, Italian, Portuguese, or French) (ages 6 to 8 years Parent PKU-QOL; ages 9 to 11 years Child PKU-QOL; ages 12 to 17 years Adolescent PKU-QOL; ages ≥18 years Adult PKU-QOL).
  • Change From Baseline in QOL Using the European Quality of Life - 5 Dimensions (EQ-5D) at Months 8, 14, 20, 26, 32, and 38 [ Time Frame: Baseline, Months 8, 14, 20, 26, 32, and 38 ]
    QOL will be assessed using the EQ-5D (EQ-5D-Y Proxy Version 1 [3 to 7 years]; EQ-5D-Y [8 to 15 years]; EQ-5D-5L ([≥16 years]).
Current Other Pre-specified Outcome Measures Not Provided
Original Other Pre-specified Outcome Measures Not Provided
 
Descriptive Information
Brief Title  ICMJE A Long-Term Safety Study of PTC923 in Participants With Phenylketonuria
Official Title  ICMJE A Phase 3 Open-Label Study of PTC923 (Sepiapterin) in Phenylketonuria
Brief Summary The main purpose of this study is to evaluate the long-term safety of PTC923 in participants with phenylketonuria, and to evaluate the changes from baseline in dietary phenylalanine (Phe)/protein consumption.
Detailed Description

Eligible participants are:

Feeder participants: those who have completed a Phase 3 PTC Therapeutics (PTC) sponsored feeder study (including Study PTC923-MD-003-PKU).

Non-feeder controlled participants: those who have not completed a feeder study and have blood Phe levels <360 μmol/L at study entry.

Non-feeder uncontrolled participants: those who have not completed a feeder study and have blood Phe levels ≥360 μmol/L at study entry.

Study Type  ICMJE Interventional
Study Phase  ICMJE Phase 3
Study Design  ICMJE Allocation: N/A
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Condition  ICMJE Phenylketonuria
Intervention  ICMJE Drug: PTC923
PTC923 powder for oral use will be suspended in water or apple juice prior to administration.
Other Name: Sepiapterin
Study Arms  ICMJE Experimental: PTC923
Participants will receive PTC923 7.5 mg/kg (participants 0 to <6 months of age), 15 mg/kg (participants 6 to <12 months of age), 30 mg/kg (participants 12 months to <2 years of age), or 60 mg/kg (participants ≥2 years of age) orally once daily for a minimum of 12 months or until participant experiences lack of efficacy, adverse events (AEs) that lead to discontinuation, withdraws from treatment, or PTC923 is authorized and commercially available in the specific country.
Intervention: Drug: PTC923
Publications * Not Provided

*   Includes publications given by the data provider as well as publications identified by ClinicalTrials.gov Identifier (NCT Number) in Medline.
 
Recruitment Information
Recruitment Status  ICMJE Recruiting
Estimated Enrollment  ICMJE
 (submitted: December 8, 2021)
200
Original Estimated Enrollment  ICMJE Same as current
Estimated Study Completion Date  ICMJE February 7, 2025
Estimated Primary Completion Date February 7, 2025   (Final data collection date for primary outcome measure)
Eligibility Criteria  ICMJE

Inclusion Criteria:

  • Clinical diagnosis of PKU with hyperphenylalaninemia (HPA) documented by past medical history of at least 2 blood Phe measurements ≥600 μmol/L.
  • Women of childbearing potential must have a negative pregnancy test at screening and agree to abstinence or the use of at least one highly effective form of contraception for the duration of the study, and for up to 90 days after the last dose of the study drug.
  • Males who are sexually active with women of childbearing potential who have not had a vasectomy must agree to use a barrier method of birth control during the study and for up to 90 days after the last dose of study drug. Males must also refrain from sperm donations during this time period.
  • Willing to continue current diet unchanged while participating in the study (unless specifically instructed to change diet during the study by the investigator).

Exclusion Criteria:

  • Inability to tolerate oral medication.
  • A female who is pregnant or breastfeeding, or considering pregnancy.
  • Serious neuropsychiatric illness (for example, major depression) not currently under medical control, that in the opinion of the investigator or sponsor, would interfere with the participant's ability to participate in the study or increase the risk of participation for that participant.
  • Past medical history and/or evidence of renal impairment and/or condition including moderate/severe renal insufficiency (glomerular filtration rate [GFR] <60 milliliters [mL]/minute [min] min as estimated most recently during qualifying participation in a feeder study) and/or under care of a nephrologist.
  • Any other condition that in the opinion of the investigator or sponsor, would interfere with the participant's ability to participate in the study or increase the risk of participation for that participant.
  • Requirement for concomitant treatment with any drug known to inhibit folate synthesis (for example, methotrexate).
  • Concomitant treatment with tetrahydrobiopterin (BH4) supplementation (for example, sapropterin dihydrochloride, KUVAN) or pegvaliase-pqpz (PALYNZIQ).

Additional criteria for non-feeder participants who did not participate in a feeder study:

  • Gastrointestinal disease (such as irritable bowel syndrome, inflammatory bowel disease, chronic gastritis, and peptic ulcer disease, etc) that could affect the absorption of study drug.
  • History of gastric surgery, including Roux-en-Y gastric bypass surgery or an antrectomy with vagotomy, or gastrectomy.
  • History of allergies or adverse reactions to synthetic BH4 or sepiapterin.
  • Any clinically significant laboratory abnormality as determined by the investigator.
  • Any abnormal physical examination and/or laboratory findings indicative of signs or symptoms of renal disease, including calculated GFR <60 milliliters (mL)/minute/1.73 square meter (m^2).

Confirmed diagnosis of a primary BH4 deficiency as evidenced by biallelic pathogenic mutations in 6-pyruvoyltetrahydropterin synthase, recessive GTP cyclohydrolase I, sepiapterin reductase, quinoid dihydropteridine reductase, or pterin-4-alphacarbinolamine dehydratase genes.

Sex/Gender  ICMJE
Sexes Eligible for Study: All
Ages  ICMJE Child, Adult, Older Adult
Accepts Healthy Volunteers  ICMJE No
Contacts  ICMJE
Contact: Patient Advocacy 1-866-562-4620 medinfo@ptcbio.com
Listed Location Countries  ICMJE Australia,   Brazil,   Canada,   Denmark,   Georgia,   Germany,   Italy,   Japan,   Mexico,   Netherlands,   Portugal,   Spain,   Turkey,   United Kingdom,   United States
Removed Location Countries France
 
Administrative Information
NCT Number  ICMJE NCT05166161
Other Study ID Numbers  ICMJE PTC923-MD-004-PKU
2021-000497-28 ( EudraCT Number )
Has Data Monitoring Committee Not Provided
U.S. FDA-regulated Product
Studies a U.S. FDA-regulated Drug Product: Yes
Studies a U.S. FDA-regulated Device Product: No
IPD Sharing Statement  ICMJE Not Provided
Current Responsible Party PTC Therapeutics
Original Responsible Party Same as current
Current Study Sponsor  ICMJE PTC Therapeutics
Original Study Sponsor  ICMJE Same as current
Collaborators  ICMJE Not Provided
Investigators  ICMJE Not Provided
PRS Account PTC Therapeutics
Verification Date April 2024

ICMJE     Data element required by the International Committee of Medical Journal Editors and the World Health Organization ICTRP