Oral N-acetylcysteine for Retinitis Pigmentosa

ClinicalTrials.gov ID: NCT05537220

Public ClinicalTrials.gov record NCT05537220. Field values are reproduced from the official study page; the official ClinicalTrials.gov record remains the source of truth for eligibility, enrollment, and contact information.

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ClinicalTrials.gov public records Last synced Oct 22, 2026, 7:02 AM EDT

Data is sourced from official ClinicalTrials.gov public API records. Always review the official ClinicalTrials.gov record for the latest information.

Official title

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

Brief summary

Reproduced verbatim from the official ClinicalTrials.gov record. Not medical advice.

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 identification

NCT ID: NCT05537220
Recruitment status: Active, not recruiting
Study type: Interventional
Phase: Phase 3
Lead sponsor: Johns Hopkins University; Other
Enrollment: 485 participants

Conditions and interventions

Conditions

Retinitis Pigmentosa

Interventions

N-acetylcysteine Drug
Placebo Drug

Drug

Eligibility (public fields only)

Age range: 18 Years to 65 Years
Sex: All
Healthy volunteers: Healthy volunteers not accepted

This page does not interpret eligibility. Detailed inclusion and exclusion criteria are on the official ClinicalTrials.gov record.

Study timeline

Start date: Oct 11, 2023 (Actual)
Primary completion: May 2029 (Estimated)
Completion: May 2030 (Estimated)
Last update posted: Jun 15, 2026

2023 – 2030

United States locations

U.S. sites: 24
U.S. states: 16
U.S. cities: 24

Facility	City	State	ZIP	Site status
University of California - Davis, Department of Ophthalmology & Vision Science	Davis	California	95817	—
University of Southern California, Keck School of Medicine	Los Angeles	California	90089	—
University of California - San Francisco, Department of Ophthalmology	San Francisco	California	94158	—
Stanford University, Byers Eye Institute	Stanford	California	94303	—
Vitreo Retinal Associates	Gainesville	Florida	32607	—
University of Florida - Jacksonville, UF Health Jacksonville	Jacksonville	Florida	32209	—
University of Miami, Bascom Palmer Eye Institute	Miami	Florida	33136	—
Emory University, Emory Eye Center	Atlanta	Georgia	30322	—
University Of Illinois At Chicago	Chicago	Illinois	60612	—
Northwestern University	Evanston	Illinois	60208	—
University of Iowa, Carver College of Medicine	Iowa City	Iowa	52242	—
Wilmer Eye Institute- Johns Hopkins University	Baltimore	Maryland	21287	—
Harvard University, Mass. Eye and Ear	Boston	Massachusetts	02114	—
University of Michigan, Kellogg Eye Center	Ann Arbor	Michigan	48105	—
University of Minnesota, Department of Ophthalmology and Visual Neurosciences	Minneapolis	Minnesota	55455	—
Mayo Clinic, Department of Ophthalmology	Rochester	Minnesota	55905	—
University of Oklahoma, Dean McGee Eye Institute	Oklahoma City	Oklahoma	73104	—
Scheie Eye Institute	Philadelphia	Pennsylvania	19104	—
Vanderbilt University, Vanderbilt Eye Institute	Nashville	Tennessee	37211	—
Retina Foundation of the Southwest	Dallas	Texas	75231	—
University of Utah, Moran Eye Center	Salt Lake City	Utah	84132	—
University of Washington, Department of Ophthalmology	Seattle	Washington	98109	—
University of Wisconsin - Madison, McPherson Eye Research Institute	Madison	Wisconsin	53705	—
Medical College of Wisconsin, The Eye Institute	Milwaukee	Wisconsin	53226	—

Site contact phone numbers, emails, and investigator names are intentionally not displayed here. Open the official ClinicalTrials.gov record for site contact information.

Non-U.S. locations

This page focuses on the U.S. directory. The official record also lists 7 non-U.S. sites.

About this trial record page

What this page shows: Public field values for ClinicalTrials.gov record NCT05537220, including study identification, conditions, interventions, eligibility (age, sex, healthy volunteer), timeline, and U.S. site list.
What this page does not do: No medical advice, eligibility judgments, treatment recommendations, study quality scoring, or AI-generated medical summaries. No site contact phone numbers, emails, or investigator names.
Where the data comes from: Sourced from the official ClinicalTrials.gov public API. The official record is the source of truth.
Last refresh: Last update posted Jun 15, 2026 · Synced Oct 22, 2026

Open the official record

The complete public registry record, listed eligibility criteria, and available contact information for NCT05537220 live on ClinicalTrials.gov.

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