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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 : February 26, 2024
Sponsor:
Information provided by (Responsible Party):
PTC Therapeutics

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.

Condition or disease Intervention/treatment Phase
Phenylketonuria Drug: PTC923 Phase 3

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.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 200 participants
Allocation: N/A
Intervention Model: Single Group Assignment
Masking: None (Open Label)
Primary Purpose: Treatment
Official Title: A Phase 3 Open-Label Study of PTC923 (Sepiapterin) in Phenylketonuria
Actual Study Start Date : February 14, 2022
Estimated Primary Completion Date : February 7, 2025
Estimated Study Completion Date : February 7, 2025


Arm Intervention/treatment
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.
Drug: PTC923
PTC923 powder for oral use will be suspended in water or apple juice prior to administration.
Other Name: Sepiapterin




Primary Outcome Measures :
  1. 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

  2. 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).


Secondary Outcome Measures :
  1. 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).

  2. 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]).



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Ages Eligible for Study:   Child, Adult, Older Adult
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No
Criteria

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.


Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT05166161


Contacts
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Contact: Patient Advocacy 1-866-562-4620 medinfo@ptcbio.com

Locations
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Sponsors and Collaborators
PTC Therapeutics
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Responsible Party: PTC Therapeutics
ClinicalTrials.gov Identifier: NCT05166161    
Other Study ID Numbers: PTC923-MD-004-PKU
2021-000497-28 ( EudraCT Number )
First Posted: December 21, 2021    Key Record Dates
Last Update Posted: February 26, 2024
Last Verified: February 2024

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Studies a U.S. FDA-regulated Drug Product: Yes
Studies a U.S. FDA-regulated Device Product: No
Additional relevant MeSH terms:
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Phenylketonurias
Brain Diseases, Metabolic, Inborn
Brain Diseases, Metabolic
Brain Diseases
Central Nervous System Diseases
Nervous System Diseases
Amino Acid Metabolism, Inborn Errors
Metabolism, Inborn Errors
Genetic Diseases, Inborn
Metabolic Diseases