Testing N-Acetyl Cysteine for people at risk of Huntington's Disease

A Randomised Controlled Trial, Of N-Acetyl Cysteine (NAC), for Premanifest Huntingtin Gene Expansion Carriers

Phase 2 Interventional Western Sydney Local Health District · NCT05509153

This study is testing if taking N-Acetyl Cysteine can help people who are at risk for Huntington's Disease delay the start of symptoms.

Quick facts

PhasePhase 2
Study typeInterventional
Enrollment160 (estimated)
Ages18 Years and up
SexAll
SponsorWestern Sydney Local Health District Academic / other
Locations5 sites (Westmead, New South Wales and 4 other locations)
Trial IDNCT05509153 on ClinicalTrials.gov

What this trial studies

This phase II randomized controlled trial investigates the effects of oral N-Acetyl Cysteine (NAC) on premanifest carriers of the Huntington gene. Participants will be monitored for clinical and radiological outcomes over a three-year period. The study aims to determine whether NAC can delay the onset of Huntington's Disease symptoms in individuals who are genetically predisposed but currently asymptomatic. The trial includes a placebo group for comparison to assess the efficacy of NAC.

Who should consider this trial

Good fit: Ideal candidates are individuals who are carriers of the Huntington gene expansion with 39 or more CAG repeats and show no clear motor signs of the disease.

Not a fit: Patients who have already been diagnosed with clinical Huntington's Disease will not benefit from this study.

Why it matters

Potential benefit: If successful, this study could provide a new therapeutic option to delay the onset of Huntington's Disease in at-risk individuals.

How similar studies have performed: While there have been studies exploring NAC for various neurological conditions, this specific approach for premanifest Huntington's Disease is novel and has not been extensively tested.

Eligibility criteria

Show full inclusion / exclusion criteria
Inclusion Criteria:

* Able to provide informed consent
* Huntingtin gene expansion carrier with \>= 39 CAG repeats
* Absence of unequivocal motor signs of HD - that is, UHDRS
* Diagnostic Confidence Level needs to be \<4 upon enrolment
* Expected to develop clinical HD within 10 years of trial enrolment using the Langbehn formula
* Availability of an informant for corroborative history
* Negative serum pregnancy test for women of childbearing potential
* If of childbearing potential, is able and agrees to remain abstinent or use adequate contraceptive methods
* Ability to tolerate MRI scans
* Ability to tolerate blood draws
* Able to comply with all study protocol requirements, according to the investigators judgement
* In the opinion of the investigator, medically, psychiatrically and neurologically stable at the time of enrolment

Exclusion Criteria:

* Diagnosis of clinical HD
* Known hypersensitivity to NAC
* Pregnancy, breastfeeding or intention to do so prior to the end of the study
* Exposure to any investigational drugs within 30 days of Baseline Visit
* Use of supplemental NAC
* Abnormalities in laboratory measurements, ECG or vital signs at screening, which precludes safe participation in the study
* Current or history of substance abuse within one year of Baseline visit
* Unstable psychiatric or acute medical illness including cancer, as determined by investigator
* Current use of antipsychotic medications or Tetrabenazine
* History of gene therapy, cell transplantation, or any experimental brain surgery
* History of attempted suicide or suicidal ideation within 12 months prior to screening
* Pre-existing structural brain lesion as assessed by a centrally read MRI scan during the screening period

Where this trial is running

Westmead, New South Wales and 4 other locations

Study contacts

How to participate

  1. Review the eligibility criteria above with your treating physician.
  2. Visit the official trial page on ClinicalTrials.gov for the most current contact information and recruitment status.
  3. Contact the listed study coordinator or principal investigator to request pre-screening. Pre-screening is free and never obligates you to enroll.
Conditions Huntington DiseaseN-Acetylcysteine
Last reviewed 2026-06-13 by the Find a Trial editorial team. Information on this page is for educational purposes and is not medical advice. Always consult qualified healthcare professionals about clinical trial participation.