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    "canonicalTrial": {
      "canonicalId": "NCT05537220",
      "title": "Oral N-acetylcysteine for Retinitis Pigmentosa",
      "scientificTitle": "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",
      "status": "active",
      "studyType": "interventional",
      "phase": [
        "PHASE3"
      ],
      "conditions": [
        "Retinitis Pigmentosa"
      ],
      "interventions": [
        {
          "name": "N-acetylcysteine",
          "type": "DRUG",
          "description": "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."
        },
        {
          "name": "Placebo",
          "type": "DRUG",
          "description": "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."
        }
      ],
      "sponsor": {
        "name": "Johns Hopkins University",
        "type": "OTHER"
      },
      "locations": [
        {
          "city": "Davis",
          "country": "United States",
          "facility": "University of California - Davis, Department of Ophthalmology & Vision Science"
        },
        {
          "city": "Los Angeles",
          "country": "United States",
          "facility": "University of Southern California, Keck School of Medicine"
        },
        {
          "city": "San Francisco",
          "country": "United States",
          "facility": "University of California - San Francisco, Department of Ophthalmology"
        },
        {
          "city": "Stanford",
          "country": "United States",
          "facility": "Stanford University, Byers Eye Institute"
        },
        {
          "city": "Gainesville",
          "country": "United States",
          "facility": "Vitreo Retinal Associates"
        },
        {
          "city": "Jacksonville",
          "country": "United States",
          "facility": "University of Florida - Jacksonville, UF Health Jacksonville"
        },
        {
          "city": "Miami",
          "country": "United States",
          "facility": "University of Miami, Bascom Palmer Eye Institute"
        },
        {
          "city": "Atlanta",
          "country": "United States",
          "facility": "Emory University, Emory Eye Center"
        },
        {
          "city": "Chicago",
          "country": "United States",
          "facility": "University Of Illinois At Chicago"
        },
        {
          "city": "Evanston",
          "country": "United States",
          "facility": "Northwestern University"
        },
        {
          "city": "Iowa City",
          "country": "United States",
          "facility": "University of Iowa, Carver College of Medicine"
        },
        {
          "city": "Baltimore",
          "country": "United States",
          "facility": "Wilmer Eye Institute- Johns Hopkins University"
        },
        {
          "city": "Boston",
          "country": "United States",
          "facility": "Harvard University, Mass. Eye and Ear"
        },
        {
          "city": "Ann Arbor",
          "country": "United States",
          "facility": "University of Michigan, Kellogg Eye Center"
        },
        {
          "city": "Minneapolis",
          "country": "United States",
          "facility": "University of Minnesota, Department of Ophthalmology and Visual Neurosciences"
        },
        {
          "city": "Rochester",
          "country": "United States",
          "facility": "Mayo Clinic, Department of Ophthalmology"
        },
        {
          "city": "Oklahoma City",
          "country": "United States",
          "facility": "University of Oklahoma, Dean McGee Eye Institute"
        },
        {
          "city": "Philadelphia",
          "country": "United States",
          "facility": "Scheie Eye Institute"
        },
        {
          "city": "Nashville",
          "country": "United States",
          "facility": "Vanderbilt University, Vanderbilt Eye Institute"
        },
        {
          "city": "Dallas",
          "country": "United States",
          "facility": "Retina Foundation of the Southwest"
        },
        {
          "city": "Salt Lake City",
          "country": "United States",
          "facility": "University of Utah, Moran Eye Center"
        },
        {
          "city": "Seattle",
          "country": "United States",
          "facility": "University of Washington, Department of Ophthalmology"
        },
        {
          "city": "Madison",
          "country": "United States",
          "facility": "University of Wisconsin - Madison, McPherson Eye Research Institute"
        },
        {
          "city": "Milwaukee",
          "country": "United States",
          "facility": "Medical College of Wisconsin, The Eye Institute"
        },
        {
          "city": "Graz",
          "country": "Austria",
          "facility": "Medical University of Graz, Department of Ophthalmology"
        },
        {
          "city": "Montreal",
          "country": "Canada",
          "facility": "McGill University, The Research Institute of the McGill University Health Center"
        },
        {
          "city": "Tübingen",
          "country": "Germany",
          "facility": "University of Tübingen, Department für Augenheilkunde"
        },
        {
          "city": "Nijmegen",
          "country": "Netherlands",
          "facility": "Radboud University, Radboud University Medical Centre"
        },
        {
          "city": "Amsterdam",
          "country": "Netherlands",
          "facility": "University of Amsterdam, Amsterdam Medical Center"
        },
        {
          "city": "Basel",
          "country": "Switzerland",
          "facility": "Universitätsspital Basel, Eye Clinic"
        },
        {
          "city": "London",
          "country": "United Kingdom",
          "facility": "University College London, Moorfields Eye Hospital"
        }
      ],
      "outcomes": {
        "other": [
          "Cumulative change of EZ area assessed as the area above curve (AAC)",
          "Change in mean macular sensitivity measured by MP",
          "Change in BCVA",
          "Change in cone spacing measured by adaptive optics-scanning laser ophthalmoscopy (AOSLO)",
          "Change in cone regularity measured by AOSLO",
          "Change in cone reflectivity measured by AOSLO",
          "Proportion of eyes with ≥ 5 loci change (improvement) from baseline by ≥ 6 decibels (dB)",
          "Proportion of eyes with ≥ 5 loci change (decrease) from baseline by ≥ 6 decibels (dB)",
          "Change in patient reported outcome assessed using NEI-VFQ 25",
          "Safety of oral NAC as assessed by adverse events"
        ],
        "primary": [
          "Progressive change of ellipsoid zone (EZ) width"
        ],
        "secondary": [
          "Change in mean macular sensitivity measured by microperimetry (MP)",
          "Change in best-corrected visual acuity"
        ]
      },
      "eligibility": {
        "sex": "ALL",
        "criteria": "Inclusion Criteria:\n\nGeneral\n\n* Ability and willingness to provide informed consent\n* Age ≥ 18 and ≤65 years at time of signing Informed Consent Form\n* Ability and willingness to comply with the study protocol and to participate in all study visits and assessments in the investigator's judgement\n* For candidates of childbearing potential: willingness to use a method of contraception\n* Agreement not to take supplements other than vitamin A\n\nOcular Inclusion Criteria\n\n* Both eyes must exhibit the RP phenotype with evidence of loss of night vision, gradual constriction of visual fields, and maintenance of visual acuity;\n* In addition, an eye must meet the following criteria to be included in the study:\n* 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;\n* BCVA ≥ ETDRS letter score of 61 (20/60 Snellen equivalent);\n* Sufficiently clear ocular media and adequate pupillary dilation to allow good quality images sufficient for analysis and grading by central reading center.\n\nExclusion Criteria:\n\nGeneral Exclusion Criteria\n\n* 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\n* Renal failure requiring renal transplant, hemodialysis, peritoneal dialysis, or anticipated to require hemodialysis or peritoneal dialysis during the study\n* Liver disease, cystic fibrosis, asthma, or chronic obstructive pulmonary disease (COPD), history of thrombocytopenia not due to a reversible cause or other blood dyscrasia\n* Uncontrolled blood pressure (defined as systolic \\> 180 and/or diastolic \\> 100 mmHg while at rest) at screening. If a patient's initial measurement exceeds these values, a second reading may be taken 30 or more minutes later. If the patient's blood pressure must be controlled by antihypertensive medication, the patient may become eligible if medication is taken continuously for at least 30 days.\n* History of other disease, physical examination finding, or clinical laboratory finding giving reasonable suspicion that oral NAC may be contraindicated or that follow up may be jeopardized\n* Cerebrovascular accident or myocardial infarction within 6 months of screening\n* Participation in an investigational study that involves treatment with any drug or device within 6 months of screening\n* Three relatives already enrolled in study\n* Pregnant, breast feeding, or intending to become pregnant during the study treatment period. Women of childbearing potential who have not had tubal ligation must have a urine pregnancy test at screening.\n* Known history of allergy to NAC\n* Having taken NAC in any form in the past 4 months\n* Phenylketonuria\n* Fructose intolerance\n* Glucose-galactose malabsorption\n* Sucrase-isomaltase insufficiency\n* Abnormal laboratory value including the value of alanine aminotransferase (ALT), aspartate aminotransferase (AST), or bilirubin being greater than 1.5 x the upper limit of normal\n* Any major abnormal findings on blood chemistry, hematology, and renal function lab tests that in the opinion of the Site Investigator and/or the Study Chair makes the candidate not suitable to participate in the trial\n* HIV or hepatitis B infection\n\nOcular Exclusion Criteria\n\n* Evidence of cone-rod dystrophy or pattern dystrophy including focal areas of atrophy or pigmentary changes in the central macula\n* Cystoid spaces involving the fovea substantially reducing vision\n* Glaucoma or other optic nerve disease causing visual field loss or reduced visual acuity\n* Intra ocular pressure \\>27 mm Hg from two measurements. If a patient's initial measurement exceeds 27 mm Hg, a second reading must be taken.\n* Any retinal disease other than RP causing reduction in visual field or visual acuity\n* Any prior macular laser photocoagulation\n* Intraocular surgery within 3 months prior to screening\n* High myopia with spherical equivalent refractive error \\> 8 diopters. If an eye has had cataract surgery or refractive surgery, a pre-operative refractive error spherical equivalent \\> 8 diopters is an exclusion\n* Any concurrent ocular condition that might affect interpretation of results\n* History of uveitis in either eye",
        "maximumAge": "65 Years",
        "minimumAge": "18 Years",
        "healthyVolunteers": false
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      "enrollment": {
        "type": "ACTUAL",
        "count": 485
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      "startDate": "2023-10-11",
      "completionDate": "2030-05-01",
      "lastUpdated": "2026-06-15T00:00:00.000Z",
      "firstPosted": "2022-09-13T00:00:00.000Z",
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