Personalized Antisense Oligonucleotide Therapy for A Single Participant With ASXL3 Gene Mutation

An Open-Label Single Center, Single Participant Study of an Experimental Antisense Oligonucleotide Treatment for Bainbridge-Ropers Syndrome Due to ASXL3 Gene Variant

Status

Active, not recruiting

Phases

Phase 1Phase 2

Study type

Interventional

Source

ClinicalTrials.gov

Registry ID

NCT07197268

Enrollment

Registered

2025-09-29

Start date

2025-05-19

Completion date

2027-05-31

Last updated

2025-09-29

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

Bainbridge-Ropers Syndrome

Brief summary

This research project entails delivery of a personalized antisense oligonucleotide (ASO) drug designed for a single participant with Bainbridge-Ropers Syndrome (BRPS) due to a pathogenic, de novo nonsense variant in ASXL3

Detailed description

This is an interventional study to evaluate the safety and efficacy of treatment with an individualized antisense oligonucleotide (ASO) treatment in a single participant with BRPS due to a pathogenic, de novo nonsense variant in ASXL3

Interventions

DRUGnL-ASXL3-001

Personalized antisense oligonucleotide

Study design

Allocation

Intervention model

SINGLE_GROUP

Primary purpose

TREATMENT

Masking

NONE

Eligibility

Sex/Gender

MALE

Age

4 Years to 4 Years

Healthy volunteers

Inclusion criteria

* Informed consent/assent provided by the participant (when appropriate), and/or participant's parent(s) or legally authorized representative(s) * Ability to travel to the study site and adhere to study-related follow-up examinations and/or procedures and provide access to participant's medical records * Genetically confirmed ASXL3 genetic variant

Exclusion criteria

* Participant has any condition that, in the opinion of the Site Investigator, would ultimately prevent the completion of stud procedures

Design outcomes

Primary

Measure	Time frame	Description
Incidence of Treatment-Emergent Abnormalities in Safety Labs (CSF, chemistry, hematology, coagulation, urinalysis) [Safety and Tolerability]	Baseline to 24 months	Emergent abnormalities in laboratory analyses (results outside of normal range for CSF, chemistry, hematology, coagulation, and urinalysis)
Incidence of Treatment Emergent Abnormalities in Neurological Exam [Safety and Tolerability]	Baseline to 24 months	Changes from baseline to 12- and 24-months post nL-ASXL3-001 administration in neurological examination (changes in mental status, gait, cerebellar, cranial nerve, motor, reflex, and sensations compared to baseline)
Motor Skills	Baseline to 24 months	Change in gross motor function from baseline to 12- and 24-months post nL-ASLX3-001 administration as measured by the Vineland Adaptive Behavior Scales - Third Edition (Vineland-3) score.
Safety and Tolerability	Baseline to 24 months	Incidence and severity of treatment-emergent adverse events (AEs) from baseline to 12- and 24-months post nL-ASXL3-001 administration

Secondary

Measure	Time frame	Description
Cognition, Communication, and Behavior	Baseline to 24 months	Change in communication from baseline to 12- and 24-months post nL-ASXL3-001 administration as measured by Vineland Adaptive Behavior Scales - Third Edition (Vineland-3): growth scale values (GSVs) for Expressive Language and Receptive Language subdomains
Feeding Tolerance and Growth	Baseline to 24 months	Change in feeding tolerance and growth from baseline to 6-, 12-, 18-, and 24-months post nL-ASXL3-001 administration as measured by body mass index (BMI).
Feeding tolerance and growth	Baseline to 24 months	Change in feeding tolerance and growth from baseline to 6-, 12-, 18-, and 24-months post nL-ASXL3-001 administration as measured by % oral feeding vs G tube reported by parent feeding diary
Quality of Life	Baseline to 24 months	Change in quality of life from baseline to 6-, 12-, 18-, and 24-months post nL-ASXL3-001 administration as measured by the Quality-of-Life Inventory - Disability (QI-Disability)

Other

Measure	Time frame	Description
Swallow Function	Baseline to 24 months	Change in swallowing function from baseline to 12- and 24-months post nL-ASXL3-001 administration as measured by video fluoroscopic swallow study (VFSS)
Sleep	Baseline to 24 months	Change in Sleep from baseline to 6-, 12-, 18-, and 24-months post nL-ASXL3-001 administration as measured by parent-reported sleep diary
Vision	Baseline to 24 months	Change in vision from baseline to 12- and 24-months post nL-ASXL3-001 administration as measured by cortical vision impairment assessment

Countries

United States

Outcome results

None listed

Source: ClinicalTrials.gov · Data processed: Feb 4, 2026