A Study of PTC923 (CNSA-001) in Primary Tetrahydrobiopterin (BH4) Deficient Participants With Hyperphenylalaninemia

NCT03519711 | Completed Phase 1 Results DMC FDA Drug

• 1 other identifier: PBD-001
• Study Type: interventional
• Target: 8
• Locations: 1 country
• Sites: 4

Brief Summary

This study has been designed to demonstrate the safety, pharmacokinetics (PK) and preliminary efficacy of PTC923 (CNSA-001) in reducing blood phenylalanine concentrations in participants with hyperphenylalaninemia due to primary BH4 deficiency (PBD).

Conditions

BH4 Deficiency; Hyperphenylalaninemia

Outcome Measures

Primary Outcomes (1)

• Number of Participants With Treatment-Emergent Adverse Events (TEAEs)

  An adverse event (AE) was any untoward medical occurrence in a participant who received study drug without regard to possibility of causal relationship. Serious adverse event (SAE) was an AE resulting in any of the following outcomes or deemed significant for any other reason: death; initial or prolonged inpatient hospitalization; life-threatening experience (immediate risk of dying); persistent or significant disability/incapacity; congenital anomaly. AEs included both SAEs and non-serious AEs. TEAEs were defined as AEs that commenced or worsened after the first dose of study drug. A summary of other non-serious AEs and all SAEs, regardless of causality is located in the 'Reported AE section'.

  From first dose of study drug (Day 1) up to 30 (±3) days after last dose of study drug (up to 50 days)

Secondary Outcomes (9)

• Maximum Observed Plasma Concentration (Cmax) of PTC923 and Tetrahydrobiopterin (BH4)

  Day 1 (pre-dose, within 30 minutes of dosing), 0.5, 1, 2, 4, 6, 8 hours postdose (prior to Day 1 evening dose), and 24 hours postdose (prior to Day 2 morning dose)

• Cmax of Phenylalanine (Phe) and Tyrosine (Tyr)

  Day 1 (pre-dose, within 30 minutes of dosing), 0.5, 1, 2, 4, 6, 8 hours postdose (prior to Day 1 evening dose), 24 hours postdose (prior to Day 2 morning dose), 72 hours postdose (Day 4), on Day 7, and at the end of study (48 hours after last dose)

• Area Under the Curve From Time 0 to the Time of the Last Quantifiable Concentration (AUC0-last) of PTC923 and BH4

  Day 1 (pre-dose, within 30 minutes of dosing), 0.5, 1, 2, 4, 6, 8 hours postdose (prior to Day 1 evening dose), and 24 hours postdose (prior to Day 2 morning dose)

• AUC0-last of Phe and Tyr

  Day 1 (pre-dose, within 30 minutes of dosing), 0.5, 1, 2, 4, 6, 8 hours postdose (prior to Day 1 evening dose), 24 hours postdose (prior to Day 2 morning dose), 72 hours postdose (Day 4), on Day 7, and at the end of study (48 hours after last dose)

• Time to Reach Cmax (Tmax) of PTC923 and BH4

  Day 1 (pre-dose, within 30 minutes of dosing), 0.5, 1, 2, 4, 6, 8 hours postdose (prior to Day 1 evening dose), and 24 hours postdose (prior to Day 2 morning dose)

Study Arms (2)

Cohort 1: PTC923 2.5 and 10 mg/kg/day

EXPERIMENTAL

Participants will receive PTC923 suspension 2.5 milligrams (mg)/kilogram (kg)/day (dose divided in 2 for twice daily administration) orally for 7 days in Period 1, undergo a 3 (±1) day washout period, then escalate to a dose of 10 mg/kg/day (dose divided in 2 for twice daily administration) administered orally for 7 days in Period 2 (14 days total treatment).

Drug: PTC923

Cohort 2: PTC923 5 and 20 mg/kg/day

EXPERIMENTAL

Participants will receive PTC923 suspension 5 mg/kg/day (dose divided in 2 for twice daily administration) orally for 7 days in Period 1, undergo a 3 (±1) day washout period, then escalate to a dose of 20 mg/kg/day (dose divided in 2 for twice daily administration) administered orally for 7 days in Period 2 (14 days total treatment).

Drug: PTC923

Interventions

PTC923 DRUG

PTC923 will be administered per dose and schedule specified in arm description.

Also known as: CNSA-001, Sepiapterin

Cohort 1: PTC923 2.5 and 10 mg/kg/day; Cohort 2: PTC923 5 and 20 mg/kg/day

Eligibility Criteria

• Age: 12 Months+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Child (0-17), Adult (18-64), Older Adult (65+)

You may qualify if:

• Male or female participants 18 years old and above and 12 months old and above for the remaining participants (age reduction pending analysis of safety, PK, and response, in the adult participant(s) by the Data Safety Monitoring Board (DSMB) and Food and Drug Administration \[FDA\])
• Confirmed diagnosis of PBD as evidenced by medical history of biallelic pathogenic mutations in PTPS or recessive GTP-CH genes, abnormal enzymatic activity of the PTPS or GTP-CH enzymes, or a cerebrospinal fluid (CSF) biochemical profile indicative of PTPS or GTP-CH deficiencies
• Informed consent and assent (if necessary) with parental consent
• Females must be either postmenopausal for ≥1 year, or surgically sterile (tubal ligation, hysterectomy, or bilateral oophorectomy) for at least 6 months or, if of childbearing potential and not abstinent, willing to use at least 2 of the following highly effective methods of contraception (including adolescents 12 to 18 years old) from screening through 30 days after the last dose of study drug:
• Hormonal contraception (stable dose for 3 months)
• Intrauterine device/intrauterine hormone-releasing system
• Barrier contraceptive method (diaphragm, cervical cap, contraceptive sponge, condom) with spermicidal foam/gel/cream/suppository Males and females who are abstinent will not be required to use a second contraceptive method unless they become sexually active.
• Males with female partners of childbearing potential must agree to use barrier contraceptive (that is, condom) with spermicidal foam from screening through 90 days after the last dose of study drug. Males must also refrain from sperm donations during this time period.
• Females with a negative pregnancy test at screening and on Day 1 prior to dosing
• Creatinine clearance (CrCl) \>90 milliliters (mL)/minute (min) as estimated using the Cockcroft-Gault equation (≥18 years) or Schwartz-Lyon equation (≥12 months \<18 years)
• The participant is clinically stable on therapy for management of their signs and symptoms of PBD as determined by the investigator.
• The participant is willing and able to comply with the protocol.
• No tobacco use (for example; cigarettes, e-cigarettes, cigars, smokeless tobacco) for 2 weeks prior to the screening visit and willingness to abstain from these products through the last dose of study drug

You may not qualify if:

• PBD caused by biallelic pathogenic mutations in PCD, SR, DHPR, or single dominant mutations in GTP-CH
• Significant chronic medical illness other than PBD, as determined by the investigator
• Gastrointestinal disease (such as irritable bowel syndrome, inflammatory bowel disease, chronic gastritis, 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
• Inability to tolerate oral medication
• History of allergies or adverse reactions to BH4 or related compounds, or any excipients in the study drug formulation
• Any clinically significant medical or psychiatric condition or medical history, that in the opinion of the investigator, would interfere with the participant's ability to participate in the study or increase the risk of participation for that participant
• Known infection with human immunodeficiency virus (HIV), hepatitis B virus (HBV) or hepatitis C virus (HCV)
• Alanine aminotransferase (ALT) or aspartate aminotransferase (AST) laboratory values \>2 \* the upper limit of normal (ULN)
• Any other clinically significant laboratory abnormality unrelated to PBD at the screening visit or prior to the administration of the first dose of study drug, as determined by the investigator
• Clinically significant cardiac arrhythmia at screening or prior to the first dose of study drug
• QTcF (QT with Fridericia's correction) ≥460 milliseconds (msec) in males and ≥480 msec in females (based on the mean of triplicate measurements taken at screening)
• Resting heart rate ≤40 or ≥110 beats/minute (bpm) for ages 12 and older, ≥130 bpm for ages 3 to 12, ≥150 bpm for ages 1 to 2 years, or resting blood pressure \<85/40 millimeters of mercury (mmHg) or \>150/90 mmHg at screening or prior to the first administration of study drug
• Current participation in any other investigational drug study or participation within 30 days prior to screening
• History of alcohol or drug abuse within last 6 months prior to screening or current evidence of substance dependence as determined by the investigator

Sponsors & Collaborators

• PTC Therapeutics: lead

Study Sites (4)

University of Minnesota

Minneapolis, Minnesota, 55454, United States

Location

UT Southwestern

Dallas, Texas, 75390, United States

Location

University of Utah Hospital

Salt Lake City, Utah, 84132, United States

Location

Marshfield Clinic

Marshfield, Wisconsin, 54449, United States

Location

MeSH Terms

Conditions

Phenylketonurias

Interventions

sepiapterin

Condition Hierarchy (Ancestors)

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; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Metabolic Diseases; Nutritional and Metabolic Diseases

Results Point of Contact

• Title: Medical Information
• Organization: PTC Therapeutics, Inc.

medinfo@ptcbio.com

1-866-562-4620

Study Officials

• Neil Smith, PharmD

  Censa Pharmaceuticals

  STUDY DIRECTOR

Publication Agreements

• PI is Sponsor Employee: No
• Restriction Type: OTHER
• Restrictive Agreement: Yes

Study Design

• Study Type: interventional
• Phase: phase 1
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: April 11, 2018
• First Posted: May 9, 2018
• Study Start: January 3, 2019
• Primary Completion: October 2, 2020
• Study Completion: October 2, 2020
• Last Updated: November 14, 2023
• Results First Posted: November 14, 2023

Record last verified: 2022-05

Data Sharing

• IPD Sharing: Will not share

Locations

US (4)