Oral N-acetylcysteine for Retinitis Pigmentosa (NCT05537220) | Clinical Trial Compass
Active — Not RecruitingPhase 3
Oral N-acetylcysteine for Retinitis Pigmentosa
United States, Austria, Canada485 participantsStarted 2023-10-11
Plain-language 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.
Who can participate
Age range
18 Years – 65 Years
Sex
ALL
See this in plain English?
AI-rewrites the medical criteria so a patient or caregiver can understand them. Always confirm with the trial site.
Inclusion Criteria:
General
* Ability and willingness to provide informed consent
* Age ≥ 18 and ≤65 years at time of signing Informed Consent Form
* Ability and willingness to comply with the study protocol and to participate in all study visits and assessments in the investigator's judgement
* For candidates of childbearing potential: willingness to use a method of contraception
* Agreement not to take supplements other than vitamin A
Ocular Inclusion Criteria
* Both eyes must exhibit the RP phenotype with evidence of loss of night vision, gradual constriction of visual fields, and maintenance of visual acuity;
* In addition, an eye must meet the following criteria to be included in the study:
* Gradable EZ on a horizontal SD-OCT scan through the fovea center with width ≤ 8000 µm and ≥1500 µm and with well-defined truncation at both the nasal and temporal sides;
* BCVA ≥ ETDRS letter score of 61 (20/60 Snellen equivalent);
* Sufficiently clear ocular media and adequate pupillary dilation to allow good quality images sufficient for analysis and grading by central reading center.
Exclusion Criteria:
General Exclusion Criteria
* Active cancer within the past 12 months, except for appropriately treated carcinoma in situ of the cervix, non-melanoma skin carcinoma, or prostate cancer with Gleason score ≤ 6 and stable prostate specific antigen for \> 12 months
* Renal failure requiring renal transplant, hemodialysis, peritoneal dialysis, or anticipated to require hemodialys…
Questions worth asking your doctor
Bring these to your next appointment. They're a starting point for a shared conversation — not a sign you qualify or a recommendation to enrol.
1This trial is measuring changes in the 'ellipsoid zone width' on retinal imaging — can you explain what that measurement means for my specific type of retinitis pigmentosa and whether it's a good indicator of how my vision is actually progressing?
2Since this is a Phase 3 trial testing oral N-acetylcysteine, which is already used in other medical contexts, what does that mean for what's already known about its safety profile, and are there any risks I should be aware of for long-term daily use?
3The trial is no longer enrolling new participants — is there any way to find out when results might be published, and could those findings change your recommendations for how we manage my condition?
4N-acetylcysteine is sometimes available outside of clinical trials — is it something you'd consider prescribing now, or is it important to wait for the trial's results before we know whether it's genuinely beneficial for retinitis pigmentosa?
5Given that I can't join this specific trial, are there other active studies or treatment approaches for retinitis pigmentosa that you think I should be considering right now based on where my condition currently stands?
Generated to help you prepare — always confirm anything about your own eligibility and care with the study team and your doctor.
Questions for the trial coordinator
The trial coordinator is the person who runs the study day to day. These cover the practical side — logistics, costs, and what taking part would actually mean for your life. The study team confirms whether you meet the criteria; these are questions to ask, not a sign you qualify.
1What does taking part actually involve week to week — how many visits, where, and how long does each one take?
2What costs are covered by the study, and what might I have to pay for myself, including travel, parking, or time off work?
3What happens during screening, and what happens if the study team confirms I don't meet the criteria after those tests?
4Who pays for the scans, blood work, and other tests the trial requires — the study, my insurance, or me?
5How will being in the trial affect my regular care, and will my own doctor stay informed and involved?
6Can I leave the trial at any point if I change my mind, and what would happen to my care if I do?
A starting point for the conversation — always confirm anything about your own eligibility, costs, and care with the study team and your doctor.