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NCT Number: NCT05664789

Targeting the Neurobiology of RRB in Autism Using N-acetylcysteine: Trial

The goal of this study is to target the neurobiology of restricted and repetitive behaviors in children with autism spectrum disorder using N-acetylcysteine (NAC), a well-tolerated nutritional supplement that has shown promise for reducing symptom severity in recent small-scale trials. The findings from this research will shed light on the mechanisms of action underlying the clinical benefits of NAC and the effects of NAC on altering restricted and repetitive behavior symptom severity in children with autism spectrum disorder. This is a 12-week double-blind, randomized, placebo-controlled trial of NAC.

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Key information

Age range

3 year–12 year

Sex eligibility

All sexes

Study type

Interventional

Phase

Phase 2 / Phase 3

Primary location

Department of Psychiatry and Behavioral Sciences

Palo Alto, California, 94304, United States

Location status: Recruiting

Location contact

Ramy Chebbo

CONTACT

[email protected]

(650)723-7845

Who can participate

Healthy volunteers accepted: No

Only the study team can determine whether someone qualifies for participation.

Inclusion criteria

  • children between 3 years and 12 years 11 months
  • diagnosis of autism spectrum disorder confirmed with the Autism Diagnostic Interview- Revised and the Autism Diagnostic Observation Schedule-2, Brief Observation of Symptoms of Autism, or Childhood Autism Rating Scale
  • at least moderate severity of restricted and repetitive behaviors defined by a Children's Yale-Brown Obsessive Compulsive Scale for Autism Spectrum Disorder score ≥ 11
  • physical development indicative of prepubescence as defined by criteria for Tanner Stage 1
  • if home address is within 300 miles of the primary study site, participants must pass MR safety screening (e.g., no metal in the body) and attempt baseline neuroimaging (MRI or EEG), otherwise baseline neuroimaging is not required for participation
  • have stable medication regimens (≥ 30 days) and psychosocial treatments (≥ 60 days) prior to randomization with no anticipated changes during the trial

Exclusion criteria

  • presence of known genetic abnormalities associated with ASD (e.g. Fragile X)
  • current or life-time diagnosis of severe psychiatric disorder (e.g., schizophrenia)
  • presence of significant medical problems
  • the inability of at least one caregiver to speak and read English to a sufficient level
  • participants taking glutathione agents/prodrugs
  • history of any adverse effects to glutathione agents/prodrugs
  • the inability to drink a sample study compound dissolved in liquid

Treatment and study plan

n acetyl cysteine

Drug

N-acetylcysteine (NAC) is an over-the-counter dietary supplement that is relatively well tolerated and exhibits minimal side effects, even at high dosages. N

Placebo

Drug

matched placebo

Primary outcomes

  1. Change in Children's Yale Brown-Obsessive Compulsive Scale for Autism Spectrum Disorder (CYBOCS-ASD) at 12 weeks

    Time frame: Screening and week 12

    Severity of restricted and repetitive behaviors, higher scores indicate more severe behaviors

  2. Change in Glutamatergic neurometabolites at 12 weeks

    Time frame: Baseline and week 12

    Glu and Glx measured by magnetic resonance imaging

Secondary outcomes

  1. Change in Restricted and Repetitive Behavior Scale Revised (RBS-R) at 12 weeks

    Time frame: Baseline and week 12

    Severity of restricted and repetitive behaviors, higher scores indicate more severe behaviors

  2. Change in Gamma band activity at 12 weeks

    Time frame: Baseline and week 12

    Electrical activity between 30-48 Hz measured by electroencephalography

Study contacts

Contact information is provided by the study sponsor or research team.

John Hegarty, PhD

CONTACT

[email protected]

(650)723-7845

Ramy Chebbo

CONTACT

[email protected]

(650)723-7845

Sponsors and collaborators

Lead sponsor

Stanford University

Other

Collaborators

  • Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)

Registry information

Official study title

Targeting the Neurobiology of Restricted and Repetitive Behaviors in Children With Autism Using N-acetylcysteine: A Randomized, Controlled Trial

Important dates

Study start
2023
Primary completion
2028
Study completion
2028
First posted
Dec 27, 2022
Registry last updated
May 15, 2026

OpenTrials presents study information sourced from ClinicalTrials.gov. The official registry record should be consulted for the latest information.

View the official ClinicalTrials.gov record (opens in a new tab)

This listing is for discovery and informational purposes only. It is not medical advice, does not guarantee that a study is recruiting, and does not determine eligibility. Contact the study team and a qualified healthcare professional when considering participation.

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