Single Dose Double-blind, Placebo-controlled Cross-over (SDDBPCCO) Shiftability Study, Will be Followed by a 10-week Open-label Study With Arbaclofen (4 Weeks of Titration and Then 6 Weeks of Active/Stable Treatment). The Effects of Arbaclofen on Target EEG and ERG Metrics Will be Associated With th

A Follow-Up Shiftability Study of Arbaclofen With an Open-Label Extension for the Study of Biomarkers in Children and Adolescents With Autism Spectrum Disorders.

study with arbaclofen (4 weeks of titration and then 6 weeks of active/stable treatment). The effects of arbaclofen on target EEG and ERG metrics will be associated with the clinical response in measures of social and general function, adaptive behaviour, social anxiety, sensory behaviours, global functioning, and quality of life in Children and Adolescents with Autism Spectrum Disorders

Study Overview

• Status: Recruiting
• Conditions: Autism Spectrum Disorders
• Intervention / Treatment: Drug: Arbaclofen; Other: Placebo

• Study Type: Interventional
• Enrollment (Estimated): 103
• Phase: Phase 3

Contacts and Locations

Study Locations

• France
  • Paris, France, 75019
    • Recruiting
    • Assistance Publique Hopitaux De Paris
    • Contact: Richard Delorme, PhD; Phone Number: +31140034130; Email: richard.delorme@aphp.fr
    • Principal Investigator: Richard Delorme, PhD
• Spain
  • Barcelona, Spain, 08036
    • Recruiting
    • Hospital Clinic De Barcelona
    • Contact: Rosa Calvo, PhD; Phone Number: +34932279974; Email: rcalvo@clinic.cat
    • Principal Investigator: Rosa Calvo, PhD
  • Madrid, Spain, 28007
    • Recruiting
    • Hospital General Universitario Gregorio Marañon
    • Contact: Maria José Parellada, PhD; Phone Number: +34 91 4265005; Email: parelladahggm@gmail.com
    • Principal Investigator: María José Parellada, PhD
  • Salamanca, Spain
    • Recruiting
    • Hospital Universitario De Salamanca
    • Contact: Ricardo Canal-Bedia, PhD; Phone Number: +34638766776; Email: rcanal@usal.es
    • Principal Investigator: Ricardo Canal-Bedia, PhD
  • Zamora, Spain, 49020
    • Recruiting
    • Complejo Asistencial De Zamora Hospital Provincial De Zamora
    • Contact: Manuel Angel Franco, PhD; Phone Number: +34669462622; Email: mfrancom@saludcastillayleon.es
    • Principal Investigator: Manuel Angel Franco, PhD

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Child; Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

• Signed Written Informed Consent a.Participants or their legal representative must have signed and dated an IRB/IEC approved written informed consent form
• Diagnosis of an Autism Spectrum Disorder according to the DSM-5 criteria
• Participation in the AIMS-2 CT1 (ages at recruitment 5 to 17).
• Current pharmacological treatment regimen affecting behaviour has been stable for at least 6 weeks prior to screening and is expected to be stable during the duration of the study
• Current psychotherapeutic/psychosocial interventions affecting behaviour stable for 3 months prior to screening and expected to be stable during the duration of the study
• Participants with a history of seizure disorder must currently be receiving stable treatment with anticonvulsant medication and must have been seizure free for 6 months prior to screening or must be seizure free for 3 years prior to screening if not currently on a stable (>3 months) dose of antiepileptics
• Male or female participants 7 to 23 years of age at the time of providing consent, inclusive.
• Reside or regular contact (at least twice a week) with the parent/carer who is interviewed for the study.
• Negative pregnancy test for females of childbearing potential (participant has experienced onset of menses)
• Females of childbearing potential who are sexually active must agree to use a highly effective form of contraception (i.e., existing surgical sterilization, complete or abstinence or a combination of two affective forms of contraception, such as, for example, condoms plus hormonal treatment). Please, refer to Appendix 4 for a complete list of acceptable contraception methods.(protocol)
• Male participants with female partners of childbearing potential are eligible to participate if they agree to the conditions stated in section 8.2.1.(protocol)

Exclusion Criteria:

• Participants with any condition that might interfere with the conduct of the study, confound interpretation of the study results, or endanger their own well-being.
• Participants who are currently receiving treatment with racemic baclofen, vigabatrin, tiagabine, or riluzole or other GABA-related medications (e.g. gabapentin or pregabalin) other than arbaclofen in the context of AIMS-2 CT1
• Participants who are currently receiving pharmacologic treatment affecting behaviour (see concomitant medication section) need to have a stable dose during the 6 weeks prior to the screening visit and for the duration of the study.
• Participating in programs including non-pharmacologic educational, behavioural, and/or dietary interventions affecting behaviour, participation in these programs must have been continuous during the 3 months prior to screening and participants or their parent/caregiver/LAR may not electively initiate new or modify ongoing interventions for the duration of the study. Typical school vacations are not considered modifications of stable programming
• Participants who have taken another investigational drug within the last 30 days.
• Participants with evidence of any significant haematological, endocrine, cardiovascular (including uncorrected symptomatic congenital heart disease), respiratory, renal, hepatic, or gastrointestinal disease, not including mild common paediatric diseases in these areas that are stable (e.g. mild asthma, constipation, etc.), as judged by the investigator.
• Participants who are not able to take oral medications.
• Participants who have a history of hypersensitivity to racemic baclofen
• Participants with rare hereditary problems of galactose intolerance, the lactase deficiency or glucose-galactose malabsorption should not take this medicine.
• Active peptic ulceration as Baclofen stimulates gastric acid secretion.
• Porphyria.
• Participants who are currently engaged in illicit drug use or alcohol abuse, according to DSM-5 criteria.
• Participants who have previously participated in a clinical trial with arbaclofen (other than our AIMS-2-CT1).
• Women who are breastfeeding

Study Plan

How is the study designed?

Design Details

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

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Placebo Comparator: placebo	Other: Placebo; initial single dose placebo
Experimental: arbaclofen	Drug: Arbaclofen; initial single dose arbaclofen

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Change in power in the low frequency bands (theta/alpha) (between visits 1 and 2).	To predict long term response to arbaclofen based on a single dose response during the placebo-controlled randomized single dose double blind stage.	baseline to day 7

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Latency of N170 change (between visits 1 and 2).	To test the effect of arbaclofen on an EEG biomarker for response to faces during the placebo-controlled randomized single dose double blind stage.	baseline to day 7
Change of Autism Impact Measure (AIM total (Kanne et al., 2014b, Silkey et al., 2023) and subscales. • Change in the Social Responsiveness Scale (SRS total and subscales; Constantino & Gruber, 2012a).	To explore the effect of arbaclofen on other measures of defining features of autism.	from baseline to end of treatment
Change in power in the higher frequency bands (gamma/beta); connectivity in the theta and alpha bands; (between visits 1 and 2).	To explore EEG marker sensitive to excitatory/inhibitory changes.	baseline to day 7

Collaborators and Investigators

• Sponsor: Hospital General Universitario Gregorio Marañon
• Collaborators: Fundación para la Investigación Biomédica del Hospital Gregorio Maranon

Study record dates

Study Major Dates

• Study Start (Actual): November 20, 2025
• Primary Completion (Estimated): December 31, 2026
• Study Completion (Estimated): December 31, 2026

Study Registration Dates

• First Submitted: March 17, 2025
• First Submitted That Met QC Criteria: June 12, 2026
• First Posted (Actual): June 17, 2026

Study Record Updates

• Last Update Posted (Actual): June 17, 2026
• Last Update Submitted That Met QC Criteria: June 12, 2026
• Last Verified: June 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Mental Disorders; Neurodevelopmental Disorders; Child Development Disorders, Pervasive; Autism Spectrum Disorder; arbaclofen placarbil
• Other Study ID Numbers: AIMS-2-CT2; 2023-508407-20-00 (Other Identifier: EU Clinical trials registry)

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: YES

IPD Plan Description

De-identified data will be entered in a GDPR compliant EDC by individual sites, and after thorough checks shared with the sponsor, according to the CTA. Data will possibly be shared after thorough data cleaning and checks of de-identification of individuals, with other parties of the consortium, if participants have agreed to that in the Informed Consent Form.

Examples of these data would be EEG data, that would be uploaded in a secured server, and analysed by a consortium partner.

• IPD Sharing Time Frame: 365 days after study finalizes
• IPD Sharing Supporting Information Type: CSR

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No