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

May 13, 2026 updated by: John Patrick Hegarty, Stanford University

Targeting the Neurobiology of Restricted and Repetitive Behaviors in Children With Autism Using N-acetylcysteine: an Open Label Extension

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.

Study Overview

Status

Enrolling by invitation

Conditions

Intervention / Treatment

Study Type

Interventional

Enrollment (Estimated)

144

Phase

  • Phase 2
  • Phase 3

Contacts and Locations

This section provides the contact details for those conducting the study, and information on where this study is being conducted.

Study Locations

  • United States
    • California
      • Stanford, California, United States, 94305
        • Stanford University School of Medicine

Participation Criteria

Researchers look for people who fit a certain description, called eligibility criteria. Some examples of these criteria are a person's general health condition or prior treatments.

Eligibility Criteria

Ages Eligible for Study

3 years to 12 years (Child)

Accepts Healthy Volunteers

No

Description

Inclusion Criteria:

  • participation in an associated single-dose (IRB-54931, NCT04278898) or randomized, controlled trial of NAC (IRB- 68353, NCT05664789).
  • stable medication regimens (≥ 30 days) with no anticipated changes during the trial.

Exclusion criteria:

• the presence of significant medical problems that reduce medical stability.

Study Plan

This section provides details of the study plan, including how the study is designed and what the study is measuring.

How is the study designed?

Design Details

  • Primary Purpose: Treatment
  • Allocation: N/A
  • Interventional Model: Single Group Assignment
  • Masking: None (Open Label)

Arms and Interventions

Participant Group / Arm
Intervention / Treatment
Experimental: N-Acetylcysteine
Drug: N-acetylcysteine
12 week administration of N-Acetylcysteine to target restricted repetitive behavior severity.

What is the study measuring?

Primary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in glutamatergic neurometabolites (Glx) measured by proton spectroscopy Magnetic Resonance Imaging (MRI)
Time Frame: Baseline and Week 12 of treatment
Baseline and Week 12 of treatment
Change in restricted and repetitive behaviors as measured by Children's Yale Brown Obsessive Compulsive Scale - Autism Spectrum Disorder (CYBOCS-ASD)
Time Frame: Screening, Week 8, week 12
Higher scores on the Children's Yale Brown Obsessive Compulsive Scale - Autism Spectrum Disorder mean higher levels of restricted and repetitive behaviors (Raw Score Total Range: 0-20)
Screening, Week 8, week 12

Secondary Outcome Measures

Outcome Measure
Measure Description
Time Frame
Change in Gamma band amplitude and synchronization measured by electroencephalography (EEG)
Time Frame: Baseline, Week 12
Baseline, Week 12
Change in restricted repetitive behavior subtypes as measured by the Restricted Behavior Scale - Revised (RBS-R)
Time Frame: Baseline, week 8, week 12
Higher scores on the Repetitive Behavior Scale- Revised mean higher levels of repetitive and restricted behaviors. (Raw Score Total Range: 0 - 129)
Baseline, week 8, week 12

Collaborators and Investigators

This is where you will find people and organizations involved with this study.

Sponsor

Stanford University

Collaborators

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

Investigators

  • Principal Investigator: John Hegarty, PhD, Stanford University

Study record dates

These dates track the progress of study record and summary results submissions to ClinicalTrials.gov. Study records and reported results are reviewed by the National Library of Medicine (NLM) to make sure they meet specific quality control standards before being posted on the public website.

Study Major Dates

Study Start (Actual)

March 12, 2024

Primary Completion (Estimated)

July 31, 2028

Study Completion (Estimated)

January 31, 2029

Study Registration Dates

First Submitted

August 8, 2022

First Submitted That Met QC Criteria

August 8, 2022

First Posted (Actual)

August 10, 2022

Study Record Updates

Last Update Posted (Actual)

May 15, 2026

Last Update Submitted That Met QC Criteria

May 13, 2026

Last Verified

May 1, 2026

More Information

Terms related to this study

Keywords

Additional Relevant MeSH Terms

Other Study ID Numbers

  • IRB-64292
  • K99HD101702 (U.S. NIH Grant/Contract)

Plan for Individual participant data (IPD)

Plan to Share Individual Participant Data (IPD)?

YES

IPD Plan Description

De-Identified data will be shared with the National Database for Autism Research (NDAR)

IPD Sharing Time Frame

The data will be submitted on January 15th and July 15th each year.

IPD Sharing Access Criteria

Researchers with access to the National Database for Autism Research (NDAR) will be able to obtain the submitted data

Drug and device information, study documents

Studies a U.S. FDA-regulated drug product

Yes

Studies a U.S. FDA-regulated device product

No

This information was retrieved directly from the website clinicaltrials.gov without any changes. If you have any requests to change, remove or update your study details, please contact register@clinicaltrials.gov. As soon as a change is implemented on clinicaltrials.gov, this will be updated automatically on our website as well.

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