A Study of the Safety and Tolerability of GTX-102 in Children With Angelman Syndrome

• ClinicalTrials.gov Identifier: NCT04259281
• Recruitment Status: Active, not recruiting
• First Posted: February 6, 2020
• Last Update Posted: May 3, 2024
• Sponsor: Ultragenyx Pharmaceutical Inc
• Information provided by (Responsible Party): Ultragenyx Pharmaceutical Inc

Tracking Information

• First Submitted Date: January 31, 2020
• First Posted Date: February 6, 2020
• Last Update Posted Date: May 3, 2024
• Actual Study Start Date: February 24, 2020
• Estimated Primary Completion Date: December 2025 (Final data collection date for primary outcome measure)
• Current Primary Outcome Measures (submitted: June 13, 2023): Number of Participants with Adverse Events (AEs), Serious AEs (SAEs), Adverse Events of Special Interest (AESIs), AEs Leading to Discontinuation and Severity of AEs [ Time Frame: Up to Day 337 ]

Original Primary Outcome Measures (submitted: February 4, 2020)

• Safety: incidence of adverse events [ Time Frame: Day 128 (end of study) ]
  Number of patients with adverse events (AEs)
• Safety: incidence of serious adverse events [ Time Frame: Day 128 (end of study) ]
  Number of patients with serious adverse events (SAEs)
• Safety: severity of adverse events [ Time Frame: Day 128 (end of study) ]
  Severity of AEs

Current Secondary Outcome Measures (submitted: June 13, 2023)

Pharmacokinetics of GTX-102 over time [ Time Frame: Up to Day 337 ]

Maximum drug concentration (Cmax)

Original Secondary Outcome Measures (submitted: February 4, 2020)

Pharmacokinetics of GTX-102 [ Time Frame: Day 2, Day 3, Day 4, Day 30, Day 58, Day 86, Day 128 (end of study) ]

Maximum drug concentration (Cmax)

• Current Other Pre-specified Outcome Measures: Not Provided

Original Other Pre-specified Outcome Measures (submitted: February 4, 2020)

• Pharmacodynamics of GTX-102 [ Time Frame: Day 86 ]
  UBE3A protein levels in CSF
• Exploratory: Change in motor function by wearable device [ Time Frame: Day 128 (end of study) ]
  Ambulation measured by wearable device
• Exploratory: Change in development [ Time Frame: Change from baseline to Day 128 (end of study) on total score ]
  Developmental assessment by Bayley Scales of Infant/Toddler Development 4 (BSID-4)
• Exploratory: Change in communication [ Time Frame: Change from baseline to Day 128 (end of study) on total score ]
  Observer Reported Communication Assessment (ORCA)
• Exploratory: Seizure frequency [ Time Frame: Day 128 (end of study) ]
  Seizure frequency by diary
• Exploratory: Change in sleep [ Time Frame: Day 128 (end of study) ]
  Assessment of sleep by diary
• Exploratory: Change in behaviors [ Time Frame: Day 128 (end of study) ]
  Aberrant Behaviors Check List Community Version (ABC-C)
• Exploratory: Adaptive behaviors [ Time Frame: Change from baseline to Day 128 (end of study) on total score ]
  Vineland Adaptive Behaviors Scale-3 (VABS-3)
• Exploratory: Global Clinical Status [ Time Frame: Day 128 (end of study) ]
  Clinical Global Impression of Severity - Angelman syndrome version (CGI-S-AS)

Descriptive Information

• Brief Title: A Study of the Safety and Tolerability of GTX-102 in Children With Angelman Syndrome
• Official Title: A Phase 1/2 Open-label, Multiple-dose, Dose-escalating Clinical Trial of the Safety and Tolerability of GTX-102 in Pediatric Patients With Angelman Syndrome (AS)
• Brief Summary: The primary objective of the study is to evaluate the safety and tolerability of multiple-ascending doses of GTX-102 administered by intrathecal (IT) injection to participants with Angelman Syndrome (AS).

Detailed Description

This is a Phase 1/2, open-label, multiple-dose, study to evaluate the safety, tolerability, and plasma and CSF concentrations of GTX-102 in pediatric participants with AS.

The study includes a Loading phase followed by a Maintenance phase. Participants may continue on GTX-102 during the Maintenance phase of the study until GTX-102 is commercially available, intolerable toxicity occurs, the parent/legal guardian withdraws consent, the participant enrolls in another experimental study, or this study is terminated.

This study was previously posted by GeneTX Biotherapeutics, LLC and was transferred to Ultragenyx in July 2022.

• Study Type: Interventional
• Study Phase: Phase 1; Phase 2
• Study Design: Allocation: Non-Randomized; Intervention Model: Parallel Assignment; Masking: None (Open Label); Primary Purpose: Treatment
• Condition: Angelman Syndrome

Intervention

Drug: GTX-102

antisense oligonucleotide

Study Arms

• Experimental: GTX-102 Cohort 1
  3.3 mg starting dose followed by intra-patient dose escalation up to 36 mg and then a maintenance phase (in U.S participants 4 to <17 years of age)
  Intervention: Drug: GTX-102
• Experimental: GTX-102 Cohort 2
  10 mg starting dose followed by intra-patient dose escalation up to 36 mg and then a maintenance phase (in U.S participants 4 to <17 years of age)
  Intervention: Drug: GTX-102
• Experimental: GTX-102 Cohort 3
  20 mg starting dose followed by intra-patient dose escalation up to 55 mg and then a maintenance phase (in U.S participants 4 to <17 years of age)
  Intervention: Drug: GTX-102
• Experimental: GTX-102 Cohort 4
  3.3 mg starting dose followed by slow intra-patient dose escalation up to 5 mg and then a maintenance phase (in Ex-U.S participants 4 to <8 years of age)
  Intervention: Drug: GTX-102
• Experimental: GTX-102 Cohort 5
  5 mg starting dose followed by slow intra-patient dose escalation up to 7.5 mg and then a maintenance phase (in Ex-U.S participants ≥ 8 to 17 years of age)
  Intervention: Drug: GTX-102
• Experimental: GTX-102 Cohort 6
  7.5 mg starting dose followed by slow intra-patient dose escalation up to 10 mg and then a maintenance phase (in Ex-U.S participants 4 to <8 years of age)
  Intervention: Drug: GTX-102
• Experimental: GTX-102 Cohort 7
  10 mg starting dose followed by slow intra-patient dose escalation up to 12 mg and then a maintenance phase (in Ex-U.S participants ≥ 8 to 17 years of age)
  Intervention: Drug: GTX-102
• Experimental: GTX-102 Cohort US
  2 mg for 4 monthly doses followed by a quarterly maintenance regimen
  Intervention: Drug: GTX-102
• Experimental: GTX-102 Expanded Enrollment Cohort A
  Sponsor selected dose followed by slow intra-patient dose escalation and then a maintenance phase (in Ex-U.S participants 4 to <8 years of age)
  Intervention: Drug: GTX-102
• Experimental: GTX-102 Expanded Enrollment Cohort B
  Sponsor selected dose followed by slow intra-patient dose escalation and then a maintenance phase (in Ex-U.S participants ≥ 8 to 17 years of age)
  Intervention: Drug: GTX-102
• Experimental: GTX-102 Expanded Enrollment Cohort C
  Sponsor selected dose followed by slow intra-patient dose escalation and then a maintenance phase (in U.S participants 4 to <8 years of age)
  Intervention: Drug: GTX-102
• Experimental: GTX-102 Expanded Enrollment Cohort D
  Sponsor selected dose followed by slow intra-patient dose escalation and then a maintenance phase (in U.S participants ≥ 8 to 17 years of age)
  Intervention: Drug: GTX-102
• Experimental: GTX-102 Cohort E
  Sponsor selected dose followed by slow intra-patient dose escalation and then a maintenance phase (in participants that transition from GTX-102 US Cohort only)
  Intervention: Drug: GTX-102

• Publications *: Not Provided

Recruitment Information

• Recruitment Status: Active, not recruiting
• Actual Enrollment (submitted: January 3, 2024): 74
• Original Estimated Enrollment (submitted: February 4, 2020): 20
• Estimated Study Completion Date: December 2025
• Estimated Primary Completion Date: December 2025 (Final data collection date for primary outcome measure)

Eligibility Criteria

Inclusion Criteria:

• Signed informed consent from parent(s) or legal guardian(s)
• Documented genetic confirmation of full maternal UBE3A gene deletion causing AS in the region of 15q11.2-q13 including class I, II or III
• Stable seizure control (defined as clinically stable with no changes in antiepileptic medications over the prior 1 month before the screening visit, other than weight associated dose adjustments)
• Able to ambulate independently, or with an assistive device (note, a child whose primary means of mobility is by wheelchair is excluded from the study)
• Platelet count, prothrombin time / international normalized ratio, and partial thromboplastin time within 1.2 x the normal limits
• Normal renal function with serum creatinine and spot urine protein ≤ 1.4 x the upper limit of normal (ULN)
• Normal hepatic function with total bilirubin, aspartate aminotransferase, alanine aminotransferase, and alkaline phosphatase ≤ 1.4 x ULN. Exception: levels ≤ 2 × ULN are acceptable if due to anti-epileptic drugs (AEDs) or Gilbert syndrome
• Willing and able to comply with scheduled visits, drug administration plan, laboratory tests, study restrictions, and all study procedures, including LP procedure
• Able to tolerate the anesthetic regimen, if required for LP procedure
• A female patient is eligible to participate if she is not pregnant, not breastfeeding, and at least one of the following conditions applies: Female of non-childbearing potential (ie, pre-menarche), Female of childbearing potential who agrees to remain abstinent (refrain from heterosexual intercourse) or use acceptable contraceptive methods during the treatment period and for at least 3 months after the final dose of GTX-102
• A male patient is eligible to participate if he agrees to remain abstinent (refrain from heterosexual intercourse) or use acceptable contraceptive methods during the treatment period and for at least 3 months after the final dose of GTX-102

Exclusion Criteria:

• Any change in medications (excluding AEDs) or diet/supplements intended to treat symptoms of AS (eg, sleeping aids, supplements, dietary change including ketogenic or low-glycemic index diet, other) over the prior 1 month before screening
• Any bleeding or platelet disorder
• Any clinically significant cardiovascular, endocrine, hepatic, renal, pulmonary, gastrointestinal, neurological, malignant, metabolic, psychiatric, or other condition that, in the judgment of the Investigator, will pose a safety risk, make the patient unsuitable for participation in, and/or unable to complete the study procedures
• Any laboratory abnormality, that, in the Investigator's opinion, could adversely affect the safety of the patient, make it unlikely that the course of treatment or follow up would be completed, or impair the assessment of study result
• Known positive for hepatitis B virus, hepatitis C virus, or human immunodeficiency virus
• Any active infection
• Bone, spine, bleeding, or other disorder that exposes the patient to risk of injury or unsuccessful lumbar puncture
• Drugs that increase the risk of bleeding (eg, heparin, low molecular weight heparin, platelet inhibitors)
• Any prior use of gene therapy
• Use of any investigational drugs in the past 6 months or within 5 half-lives, whichever period is greater (with the exception of prior GTX 102)
• Known hypersensitivity to any oligonucleotide, as demonstrated by an immune mediated reaction (eg, pneumonitis, hepatitis, nephritis, neuritis, or other system inflammation), or a systemic allergic reaction such as signs and symptoms of anaphylaxis, urticaria, clinically significant rash
• Patient is pregnant or lactating
• Any medical condition that would require intubation for the anesthesia procedure

Sex/Gender

• Sexes Eligible for Study: All

• Ages: 4 Years to 17 Years (Child)
• Accepts Healthy Volunteers: No
• Contacts: Contact information is only displayed when the study is recruiting subjects
• Listed Location Countries: Australia, Canada, France, Germany, Israel, Spain, United Kingdom, United States

Administrative Information

• NCT Number: NCT04259281
• Other Study ID Numbers: GTX-102-001; 2021-001793-36 ( EudraCT Number )
• Has Data Monitoring Committee: Yes

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

• Plan to Share IPD: No

• Current Responsible Party: Ultragenyx Pharmaceutical Inc
• Original Responsible Party: GeneTX Biotherapeutics, LLC
• Current Study Sponsor: Ultragenyx Pharmaceutical Inc
• Original Study Sponsor: GeneTX Biotherapeutics, LLC
• Collaborators: Not Provided

Investigators

• Study Director: Medical Director; Ultragenyx Pharmaceutical Inc

• PRS Account: Ultragenyx Pharmaceutical Inc
• Verification Date: May 2024