CI

At a glance

ClinicalIndex Comparison Record
Phase 3Active· 485 enrolled
Drug / intervention
N-acetylcysteine +1 moredrug
Likely dose
Not stated in record
Structured eligibility isn't available for this trial yet — see the full criteria in the Eligibility tab below.

Standardized by ClinicalIndex from the ClinicalTrials.gov record · verify against the source.

Search/NCT05537220
NCT05537220Phase 3Active
CompareCT.gov

NAC Attack, A Phase III, Multicenter, Randomized, Parallel, Double Masked, Placebo-Controlled Study Evaluating the Efficacy and Safety of Oral N-Acetylcysteine in Patients With Retinitis Pigmentosa

Johns Hopkins University·interventional·Posted Sep 13, 2022·Updated Jun 15, 2026

In Brief

A Phase 3 clinical trial evaluating N-acetylcysteine and Placebo for Retinitis Pigmentosa. Active but no longer recruiting, targeting 485 participants across 31 sites in 7 countries.

Detailed Summary

Retinitis pigmentosa (RP) is an inherited retinal degeneration caused by one of several mistakes in the genetic code. Such mistakes are called mutations. The mutations cause degeneration of rod photoreceptors which are responsible for vision in dim illumination resulting in night blindness. After rod photoreceptors are eliminated, gradual degeneration of cone photoreceptors occurs resulting in gradual constriction of side vision that eventually causes tunnel vision. Oxidative stress contributes to cone degeneration. N-acetylcysteine (NAC) reduces oxidative stress and in animal models of RP it slowed cone degeneration. In a phase I clinical trial in patients with RP, NAC taken by month for 6 months caused some small improvements in two different vision tests suggesting that long-term administration of NAC might slow cone degeneration in RP. NAC Attack is a clinical trial being conducted at many institutions in the US, Canada, and Europe designed to determine if taking NAC for several years provides benefit in patients with RP.

Study Details

Study Typeinterventional
Allocation--
Masking--
Primary Purpose--
ConditionsRetinitis Pigmentosa
CountriesAustria, Canada, Germany, Netherlands, Switzerland, United Kingdom, United States
CollaboratorsNational Eye Institute (NEI), Duke University, Emory University, Massachusetts Eye and Ear Infirmary, Mayo Clinic, Medical College of Wisconsin, Retina Foundation of the Southwest, Stanford University, University of California, Davis, University of Florida, University of Iowa, University of Miami, University of Michigan, University of Minnesota, University of Oklahoma, University of Southern California, University of Utah, University of Washington, University of Wisconsin, Madison, Vanderbilt University, Vitreo Retinal Associates, PA, University of Houston, Medical University of Graz, McGill University, Universität Tübingen, Radboud University Medical Center, University of Amsterdam, University Hospital, Basel, Switzerland, University College London Hospitals, Northwestern University, University of Pennsylvania

Timeline

Phase 3Active
20232024202520262027202820292030
First PostedSep 13, 2022
Enrollment StartOct 11, 2023
Primary CompletionMay 1, 2029
Study CompletionMay 1, 2030
TodayJul 2, 2026
Enrollment to primary: 5.6 yearsPosted 3.8 years agoPrimary completion in 2.8 years

Interventions

N-acetylcysteinedrug

After randomization, participants will be given about 10-months supply of study drug (intervention), with instructions to take 3 effervescent tablets in water twice a day. They will return to the clinic at M4.5 for evaluation and then at M9, M18, M27, M36, M40.5 and M45. At each in-clinic visit, drug reconciliation will occur. At each visit at Baseline, M9, M18, M27, M36, that is, every 9 months, participants will be given another 10-month supply of study drug.

Placebodrug

After randomization, participants will be given about 10-months supply of placebo, with instructions to take 3 effervescent tablets in water twice a day. They will return to the clinic at M4.5 for evaluation and then at M9, M18, M27, M36, M40.5 and M45. At each in-clinic visit, efficacy and safety assessments will be done and drug reconciliation will occur. At baseline, M9, M18, M27, and M36 participants will be given another 10-month supply of placebo.