A Safety and Efficacy Study of GTX-102 in Subjects With Deletion- or Nondeletion-type Angelman Syndrome (AS)

Official title

A Phase 2, Open-label, Basket Study Investigating the Safety and Efficacy of GTX-102 in Adult and Pediatric Subjects With Deletion- or Nondeletion-type Angelman Syndrome

Overview

The main goal of the study is to evaluate the safety and efficacy of GTX-102 in participants with Angelman syndrome.

Detailed description

This basket study is designed to evaluate safety and efficacy of GTX-102 in participants with Angelman syndrome across genotypes and age groups. The study consists of subprotocols A, B, C and D. All subprotocols are open-label and follow the same design which includes a Screening, Loading and Maintenance period. Subprotocols A, B and C are single arm only. In subprotocol D, participants are randomized 2:1 to a GTX-102 group or a No Treatment group. The No Treatment group follows the same schedule of events as all other groups after completion of the No Treatment period. Participants from all the subprotocols have the option to continue treatment in a long-term extension study following their end of study visit.

Interventions

• Other No intervention
  During the no treatment period participants do not receive any study drug
• Drug GTX-102
  antisense oligonucleotide

Primary outcome measures

• Subprotocol A/B/C/D: Number of Participants with Treatment Emergent Adverse Events (TEAEs) and Serious Adverse Events (SAEs), Severe Events, and Events Related to Investigational Product, Procedure, and Premedication [Time frame: Up to Day 506]
• Subprotocol A Only: Bayley-4 Cognitive Without Caregiver Input Raw Score Change from Baseline at Day 338 [Time frame: Baseline, Day 338]
• Subprotocol B/D Only: Multidomain Responder Index (MDRI) Net Response at Day 338 [Time frame: Baseline, Day 338]
• Subprotocol C Only: MDRI Net Response at Day 338 [Time frame: Baseline, Day 338]

Secondary outcome measures (9)

• Subprotocol A/B/D Only: Change From Baseline at Day 338 in Bayley-4 Receptive Communication Raw Score [Time frame: Baseline, Day 338]
• Subprotocol A/B/D Only: Change From Baseline at Day 338 in Bayley-4 Gross Motor Raw Score [Time frame: Baseline, Day 338]
• Subprotocol B/D Only: Change From Baseline at Day 338 in Bayley-4 Cognitive Raw Score [Time frame: Baseline, Day 338]
• Subprotocol B/C/D Only: Change From Baseline at Day 338 in Vineland-3 Receptive Communication Raw Score [Time frame: Baseline, Day 338]
• Subprotocol B/C/D Only: Change From Baseline at Day 338 in Vineland-3 Expressive Communication Raw Score [Time frame: Baseline, Day 338]
• Subprotocol B/D: Change From Baseline at Day 338 in Aberrant Behavior Checklist-Community (ABC-C) Hyperactivity/Noncompliance Raw Score [Time frame: Baseline, Day 338]
• Subprotocol B/D Only: Change From Baseline at Day 338 in Angelman Severity Assessment (ASA) Sleep Rating [Time frame: Baseline, Day 338]
• Subprotocol B/C/D Only: Change From Baseline at Day 338 in ASA Gross Motor Rating [Time frame: Baseline, Day 338]
• Subprotocol C Only: Change From Baseline at Day 338 in ABC-C Irritability Raw Score [Time frame: Baseline, Day 338]

Eligibility criteria

Inclusion criteria

• Signed informed consent from parent(s) or legal guardian(s)
• Males and females of the following ages and genotypes at time of informed consent:

• Subprotocol A: ≥ 1 to < 4 years of age with a genetically confirmed diagnosis of deletion-type Angelman syndrome
• Subprotocol B: ≥ 4 to < 18 years of age with a genetically confirmed diagnosis of UPD/ICD Angelman syndrome
• Subprotocol C: ≥ 18 to < 65 years of age with a genetically confirmed diagnosis of Angelman syndrome, any genotype
• Subprotocol D: ≥ 4 to < 18 years of age with a genetically confirmed diagnosis of mutation-type Angelman syndrome
• Weight ≥ 8 kg at Screening Visit
• Platelet count, prothrombin time / international normalized ratio, and partial thromboplastin time < 1.5x the upper limit of normal and platelets > 75,000 cells/mm3 at the Screening Visit
• Willing and able to comply with scheduled visits, drug administration plan, laboratory tests, and all study procedures, including lumbar puncture (LP) procedure, magnetic resonance imaging (MRI) and tolerating anesthesia without intubation
• From the time of informed consent through to at least 6 months after the final dose of GTX-102, females of childbearing potential who are sexually active must use highly effective contraception or abstinence. Males are able to participate if they agree to remain abstinent (refrain from heterosexual intercourse) or use acceptable contraceptive methods during the study and for at least 3 months after the final dose of GTX-102

Exclusion criteria

• Any change in medications or diet/supplements intended to treat symptoms of Angelman Syndrome (eg, sleeping aids, antiseizure medications, supplements, dietary change including ketogenic or low-glycemic index diet, other) within the month prior to the Screening Visit (excluding weight-based adjustments)
• Any condition that creates an increased risk of unsuccessful lumbar puncture
• Current or expected concomitant use of drugs that increase the risk of bleeding (eg, heparin, low molecular weight heparin, platelet inhibitors)
• Known hypersensitivity to GTX-102 or its excipients or required premedication that, in the judgment of the Investigator, places the subject at increased risk for adverse effects
• Presence or history of any condition, lab abnormality, or infection that, in the judgment of the Investigator, would interfere with study participation, pose undue safety risk, or would confound interpretation of results
• Pregnant or breastfeeding or planning to become pregnant (self or partner) at any time during the study
• Use of any investigational product or investigational medical device within 6 months or 5 half-lives prior to the Screening Visit, or any prior use of gene therapy or an ASO regardless of length of time since last use
• Concurrent participation in any interventional study

Criteria are shown verbatim from the registry (in English). Final eligibility is always assessed by the study center.

Healthy volunteers: No

Study design

Allocation

Randomized

Model

Parallel assignment

Masking

Open label

Primary purpose

Treatment

Study locations

United States · 8 centers

• Cedars Sinai Medical Center — Los Angeles
• Rush University Medical Center — Chicago
• Kennedy Kreiger Institute — Baltimore
• Clinical Trial Site — Kansas City
• Rare Disease Research — Hillsborough
• Akron Children's Hospital — Akron
• UT Health Austin — Austin
• Carum Research Inc. — Dallas

Italy · 3 centers

• Azienda Ospedaliera Universitaria Meyer IRCCS — Florence
• Fondazione IRCCS Istituto Neurologico C. Besta — Milan
• Clinical Trial Site — Rome

Brazil · 2 centers

• Hospital de Crianças César Pernetta e Hospital Pequeno Príncipe — Curitiba
• Casa dos Raros — Santa Cecília

France · 2 centers

• Hopital de la Timone — Marseille
• Necker-Enfants Malades Hospital — Paris

Portugal · 2 centers

• Hospital de Santa Maria — Lisbon
• Hospital Santa Joao — Porto

United Kingdom · 2 centers

• Clinical Trial Site — London
• University of Oxford — Oxford

Argentina · 1 center

• Hospital Universitario Austral — Pilar

Israel · 1 center

• Sheba Medical Center — Ramat Gan

Identifiers

NCT: NCT07157254 · GTX-102-CL210 · 2024-519393-39-00

Primary sources (government registries)

• ClinicalTrials.gov (US NIH)

View this study on ClinicalTrials.gov ↗