Autism Spectrum DisorderPhase 2/3NCT05494398
Targeting the Neurobiology of RRB in Autism Using N-acetylcysteine: Open Label
A Phase 2/3 study testing N-acetylcysteine in people with Autism Spectrum Disorder, run by Stanford University at 1 site in United States.
Trial summary
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. Read more about this study
- Who is it for?
- Ages 3 to 13 years
- Conditions the study is for
- Autism Spectrum Disorder
- What is being tested?
- N-acetylcysteine
- Could I receive a placebo?
- No, everyone receives an active treatment
- How many people
- 144 participants
- Where
- 1 siteUnited States
- Study dates
- 12 Mar 2024to 31 Jan 2029
- Phase
- Phase 2/3
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 3 to 13 years
- All sexes
- No healthy volunteers
- Child
Who may be able to join
- 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.
Who cannot join
- the presence of significant medical problems that reduce medical stability.
Trial locations and contacts
1 site in 1 country. Contact the study team or a site near you to ask about taking part.
United States1 site
Stanford University School of Medicine
Stanford, California, 94305
About this study
Official title: 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.
- Conditions
- Autism Spectrum Disorder
- Being tested
- N-acetylcysteine
- Keywords
- Magnetic Resonance Imaging, N-acetylcysteine, Restricted and Repetitive Behaviors, Electroencephalography
- Medical subject headings
- Autism Spectrum Disorder
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
N-acetylcysteineDrug
12 week administration of N-Acetylcysteine to target restricted repetitive behavior severity.
| Study group | Role | What they receive |
|---|---|---|
| N-Acetylcysteine | Experimental | Not described Receives: Drug: N-acetylcysteine |
What is being measured
The primary outcome is the main question the study is designed to answer.
Change in glutamatergic neurometabolites (Glx) measured by proton spectroscopy Magnetic Resonance Imaging (MRI)
Measured: 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)
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)
Measured: Screening, Week 8, week 12
Secondary outcomes (2)
Change in Gamma band amplitude and synchronization measured by electroencephalography (EEG)
Measured: Baseline, Week 12
Change in restricted repetitive behavior subtypes as measured by the Restricted Behavior Scale - Revised (RBS-R)
Higher scores on the Repetitive Behavior Scale- Revised mean higher levels of repetitive and restricted behaviors. (Raw Score Total Range: 0 - 129)
Measured: Baseline, week 8, week 12
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted10 Aug 2022
- Study start12 Mar 2024
- Primary completion31 Jul 2028 (estimated)
- Study completion31 Jan 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Autism Spectrum DisorderStudies of the same condition, open and under way.
- More trials run by Stanford UniversityThe sponsor's other registered studies.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 2/3
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Enrolment
- 144 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Stanford University
- Sponsor type
- University, hospital or other
- Collaborators
- Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
- Responsible party
- Principal investigator, John Patrick Hegarty, Stanford University
- Investigators
- John Hegarty, PhD, Principal investigator, Stanford University
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT05494398
- Sponsor's protocol ID
- IRB-64292
- Other IDs
- K99HD101702
- Status last verified
- May 2026
- First submitted
- 8 Aug 2022
- Last updated
- 15 May 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- Yes: De-Identified data will be shared with the National Database for Autism Research (NDAR)
Study at a glance
From the registry record, last updated by the sponsor on 15 May 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- Targeting the Neurobiology of Restricted and Repetitive Behaviors in Children With Autism Using N-acetylcysteine: an Open Label Extension
- ClinicalTrials.gov ID
- NCT05494398
- Acronym / sponsor ID
- IRB-64292
- Conditions
- Autism Spectrum Disorder
- Keywords
- Magnetic Resonance Imaging, N-acetylcysteine, Restricted and Repetitive Behaviors, Electroencephalography
- Phase
- Phase 2/3
- Study type
- Interventional
- Recruitment status
- Enrolling by invitation
- Enrolment
- 144 participants (estimated)
- Lead sponsor
- Stanford UniversityUniversity, hospital or other
- Collaborators
- Eunice Kennedy Shriver National Institute of Child Health and Human Development (NICHD)
- Study start
- 12 Mar 2024 (actual)
- Primary completion
- 31 Jul 2028 (estimated)
- Study completion
- 31 Jan 2029 (estimated)
- First posted
- 10 Aug 2022 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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 design
- Primary purpose
- Treatment
- Allocation
- Not applicable
- Intervention model
- Single group
- Masking
- None (open label)
- Number of arms
- 1
| Arm | Type | Receives |
|---|---|---|
| N-Acetylcysteine | Experimental | Drug: N-acetylcysteine |
Who may qualify
- Ages
- 3 to 13 years
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Child
Key inclusion criteria (2 listed)
- 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.
Key exclusion criteria (1 listed)
- the presence of significant medical problems that reduce medical stability.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| N-acetylcysteine12 week administration of N-Acetylcysteine to target restricted repetitive behavior severity. | Drug | N-Acetylcysteine |
Primary outcome
Change in glutamatergic neurometabolites (Glx) measured by proton spectroscopy Magnetic Resonance Imaging (MRI)
Time frame: 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)
2 secondary outcomes
Change in Gamma band amplitude and synchronization measured by electroencephalography (EEG)
Time frame: 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
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 15 May 2026.
- Individual participant dataSharing planned: Yes. De-Identified data will be shared with the National Database for Autism Research (NDAR)
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
John Hegarty, PhD principal investigator
Stanford University
1 site in 1 country: see every site and its status.
Questions about this trial
What is this clinical trial studying?
A Phase 2/3 study testing N-acetylcysteine in people with Autism Spectrum Disorder, run by Stanford University at 1 site in United States.
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 2 inclusion and 1 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: enrolling by invitation, as of the sponsor's last update on 15 May 2026. Status can change between updates, so confirm with the study contact before making plans.
Where is the study taking place?
The record lists 1 site in United States. Whether a site is taking part right now should be confirmed with that site. See every site.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this combined phase mean?
Phase 2 studies give the treatment to a larger group to see whether it has the intended effect and to keep checking safety.
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
Change in glutamatergic neurometabolites (Glx) measured by proton spectroscopy Magnetic Resonance Imaging (MRI) (time frame: Baseline and Week 12 of treatment). The study lists 2 primary outcomes in all. It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 15 May 2026.