Arbaclofen vs. Placebo in the Treatment of Children and Adolescents With ASD (ARBA) (ARBA)

A Randomized Placebo-controlled Trial of ARBaclofen vs. Placebo in the Treatment of Children and Adolescents With ASD

This study will examine the safety and efficacy of arbaclofen vs. placebo on social function in children and adolescents with Autism Spectrum Disorder (ASD).

Study Overview

• Status: Completed
• Conditions: Autism Spectrum Disorder
• Intervention / Treatment: Drug: Arbaclofen; Other: Placebo

Detailed Description

There are no pharmacologic treatments available for social function deficits in individuals with ASD. The data for pharmacologic treatment of repetitive behaviours in this disorder has also become difficult to interpret given that the last two large multisite trials of selective serotonin reuptake inhibitors (SSRIs) in autism are reported to be negative for the treatment of repetitive behaviours. Only the associated symptom of irritability has 2 drugs with Food and Drug Administration (FDA) indications, whereas no systematic data exists on the pharmacologic treatment of anxiety in ASD, and response to rates to stimulants for hyperactivity are lower than what is seen in Attention Deficit Hyperactivity Disorder (ADHD). In addition, there are no biological markers of treatment response identified in this population at this point. This study will examine the potential efficacy and safety of arbaclofen for social function, and will explore biological markers of safety and treatment response.

• Study Type: Interventional
• Enrollment (Actual): 90
• Phase: Phase 2

Contacts and Locations

Study Locations

• Canada
  • Ontario
    • Hamilton, Ontario, Canada, L8S 4K1
      • McMaster University, Offord Centre for Child Studies
    • Kingston, Ontario, Canada, K7M 8A6
      • Queen's Universtiy
    • London, Ontario, Canada, N6A 5W9
      • University of Western Ontario, Lawson Health Research Institute
    • Toronto, Ontario, Canada, M4G 1R8
      • Holland Bloorview Kids Rehabilitation Hospital

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: 1 year to 13 years (Child)
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1. Outpatients 5-17 years of age inclusive.
2. Meet Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition (DSM-5). DSM-5 criteria will be established by a clinician with expertise with individuals with ASD. Diagnosis will be supported by the Autism Diagnostic Observation Schedule, Second Edition (ADOS-2).
3. Complex language to qualify for ADOS-2 modules 3 or 4.
4. If already receiving stable concomitant medications affecting behaviour, have stable regimens with no changes during the preceding 6 weeks prior to Screening, and will not electively initiate new or modify ongoing medications for the duration of the study.
5. If already receiving stable non-pharmacological educational and behavioural interventions, have continuous participation during the preceding 3 months prior to Screening, and will not electively initiate new or modify ongoing interventions for the duration of the study.
6. Have normal physical examination and laboratory test results at Screening. If abnormal, the finding(s) must be deemed clinically insignificant by the Investigator.
7. Ability to obtain written informed consent from the participant, if developmentally appropriate. If a participant does not have the capacity to consent, ability to obtain assent (if developmentally appropriate), as well as written informed consent from their parent(s)/legal guardian(s).

Exclusion Criteria:

1. Pregnant females; sexually active females on inadequate birth control.
2. Have a serious medical condition that, based on Investigator judgment, might interfere with the conduct of the study, confound interpretation of the study results, or endanger their own well-being. Have evidence of any significant hematological, endocrine, cardiovascular (including uncorrected symptomatic congenital heart disease), respiratory, renal, hepatic, or gastrointestinal disease, not including mild common pediatric diseases in these areas that are stable (e.g. mild asthma, constipation, etc.).
3. Have unstable epilepsy (i.e. seizures occurring within the last 6 months), or have epilepsy and not on stable doses of antiepileptic medications (i.e. dose changes within the last 3 months).
4. Have a history of drug abuse.
5. Have hypersensitivity to arbaclofen or any components of its formulation.
6. Unable to tolerate venipuncture procedures for blood sampling.
7. Actively enrolled in another intervention study.
8. Taking racemic bacblofen, vigabatrin, tiagapine, riluzole, clobazam or regular benzodiazepine use (prn and hs use is allowed).
9. Unable to take oral medications.
10. Known hypersensitivity to racemic baclofen.
11. Inability to speak and understand English sufficiently enough to allow for the completion of all study assessments (parent/legal guardian; participant).

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: Quadruple

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: Placebo	Other: Placebo; Administered orally as disintegrating tabs, round, white and beveled edges
Active Comparator: Arbaclofen	Drug: Arbaclofen; Administered orally as disintegrating tabs, round, white and beveled edges, at the following strengths: 5mg, 10mg, 15mg and 20mg

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Vineland Adaptive Behavior Scales, Third Edition (Vineland-3) - Social Domain	To examine the effect of arbaclofen vs. placebo social function	16 weeks

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Clinical Global Impressions - Impression Scale - Improvement (CGI-I)	To examine the effect of arbaclofen vs. placebo on measures of global function	16 weeks
Aberrant Behavior Checklist (ABC) - Social Withdrawal Subscale	To examine the effect of arbaclofen vs. placebo on social withdrawal	16 weeks
Vineland Adaptive Behavior Scales, Third Edition (Vineland-3) - Communication Domain	To examine the effect of arbaclofen vs. placebo on communication	16 weeks
Safety Monitoring Uniform Report Form (SMURF)	To examine the safety and tolerability of arbaclofen in children and adolescents with ASD	16 weeks
Clinical Global Impressions - Impression Scale - Global (CGI-I-Global)	To examine the safety and tolerability of arbaclofen in children and adolescents with ASD	16 weeks
Epworth Sleepiness Scale for Children and Adolescents (ESS-CHAD)	To examine the safety and tolerability of arbaclofen in children and adolescents with ASD	16 weeks
Suicidality assessment using the Columbia-Suicide Severity Rating Scale (C-SSRS)	To examine the safety and tolerability of arbaclofen in children and adolescents with ASD	16 weeks

Collaborators and Investigators

• Sponsor: Holland Bloorview Kids Rehabilitation Hospital
• Collaborators: McMaster University; Unity Health Toronto; University of Toronto; Queen's University; Western University, Canada
• Investigators: Principal Investigator: Evdokia Anagnostou, M.D, Holland Bloorview Kids Rehabilitation Hospital; Principal Investigator: Robert Nicolson, M.D, University of Western Ontario, Lawson Health Research Institute; Principal Investigator: Julia Frei, M.D, McMaster University, Offord Centre for Child Studies; Principal Investigator: Muhammad Ayub, M.D, Queen's University

Study record dates

Study Major Dates

• Study Start (Actual): March 18, 2019
• Primary Completion (Actual): August 4, 2023
• Study Completion (Actual): August 4, 2023

Study Registration Dates

• First Submitted: March 21, 2019
• First Submitted That Met QC Criteria: March 21, 2019
• First Posted (Actual): March 25, 2019

Study Record Updates

• Last Update Posted (Actual): July 16, 2025
• Last Update Submitted That Met QC Criteria: July 14, 2025
• Last Verified: July 1, 2025

More Information

Terms related to this study

• Keywords: ASD; Autism
• Additional Relevant MeSH Terms: Mental Disorders; Neurodevelopmental Disorders; Child Development Disorders, Pervasive; Autism Spectrum Disorder
• Other Study ID Numbers: ARB-05-2018

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: NO

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No