24-Month Trial of NPI-001 for the Preservation of Photoreceptors in Retinitis Pigmentosa Associated With Usher Syndrome

NCT07290530 | Not Yet Recruiting Phase 3 DMC FDA Drug

• 1 other identifier: C-24-01
• Study Type: interventional
• Target: 80
• Locations: 0 countries
• Sites: N/A

Brief Summary

The goal of this clinical trial is to learn if NPI-001 works to prevent progression of retinitis pigmentosa in adults diagnosed with Usher syndrome. It will also provide information about the safety of NPI-001. The main questions it aims to answer are: Does NPI-001 slow down the loss of photoreceptors? What medical problems do participants have when taking NPI-001? Researchers will compare NPI-001 to a placebo (a look-alike substance that contains no drug) to see if NPI-001 works to preserve vision. Participants will: Take NPI-001 or a placebo twice a day, every day for 24 months Visit the clinic 9 times for checkups and tests

Conditions

Usher Syndrome; Retinitis Pigmentosa (RP)

Keywords

N-acetylcysteine amide

Outcome Measures

Primary Outcomes (1)

• EZ Area Rate of Change

  24 months

Study Arms (2)

NPI-001

EXPERIMENTAL

NPI-001 tablet, BID

Drug: N-acetylcysteine amide

Placebo

PLACEBO COMPARATOR

Placebo tablet, BID

Other: Placebo

Interventions

N-acetylcysteine amide DRUG

N-acetylcysteine amide (NPI-001) tablets (250 mg), taken BID

NPI-001

Placebo OTHER

Placebo tablets, BID

Placebo

Eligibility Criteria

• Age: 18 Years+
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• Able to comprehend and willing to sign an informed consent form (ICF) and to adhere to the study protocol.
• Diagnosed with Usher syndrome.
• EZ zone width ≥ 500 microns, which includes the fovea in each eye at Visit 1 (Screening).
• All edges of the EZ area in both eyes can be visualized at Visit 1 (Screening).
• Have at least 20 detectable points on the MAIA grid in at least one eye at the Screening and Baseline visits (same eye for both visits).
• \. On stable dose of medications associated with other conditions for at least one month.
• \. Both female participants of childbearing potential and male participants able to father children must have (or have a partner who has) had a bilateral oophorectomy, hysterectomy or bilateral salpingectomy; must abstain from intercourse; or must agree to practice 2 acceptable methods of contraception throughout the course of the study and 4 weeks after the last visit. Acceptable methods of contraception include hormonal contraception (i.e., birth control pills, injected hormones, dermal patch or vaginal ring), intrauterine device, barrier methods (diaphragm, condom) with spermicide, tubal ligation, and vasectomy.

You may not qualify if:

• Concurrent retinal pathologies that result in vision loss or inability to fixate, including but not limited to, choroideremia, retinal vein occlusion, and neovascular age-related macular degeneration.
• Intraocular surgery within the last two months or capsulotomy within the last month.
• Current or history of uveitis, Coat's disease, diabetic retinopathy, glaucoma, herpes simplex of the eye, or currently has a cataract that prevents visualization of the posterior pole.
• Likely to require cataract surgery within the next 12 months.
• Unstable fixation during microperimetry in either eye at either Screening or Baseline visits.
• Use of any other investigational new drug, or participation in another clinical trial within 12 weeks before the start of study treatment.
• Use of N-acetylcysteine containing products in the previous 30 days prior to the baseline visit or unwilling to refrain from such supplements for the duration of the study.
• Chronic liver or kidney disease, cystic fibrosis, severe asthma, or chronic obstructive pulmonary disease (COPD), history of thrombocytopenia not due to a reversible cause, or other blood dyscrasia.
• Suspected liver dysfunction determined by having alanine aminotransferase (ALT), aspartate aminotransferase (AST), or bilirubin values \> 1.5 X the upper limit of normal (ULN) at screening.
• Platelet or hemoglobin values \< 100 at screening.
• History of known sensitivity to N-acetylcysteine or similar thiol compounds or any ingredients of NPI-001.
• History of hypersensitivity to any medication or food resulting in systemic symptoms.
• History of cancer (other than non-melanoma skin cancer) diagnosed or requiring treatment within the past 2 years.
• Pregnant women or women planning to become pregnant in the next 25 months or men with partners planning to become pregnant in the next 25 months.
• Lactating women who are breast-feeding.

Sponsors & Collaborators

• Nacuity Pharmaceuticals, Inc.: lead

MeSH Terms

Conditions

Retinitis Pigmentosa; Usher Syndromes

Interventions

N-Acetylcysteinamide

Condition Hierarchy (Ancestors)

Eye Diseases, Hereditary; Eye Diseases; Retinal Dystrophies; Retinal Degeneration; Retinal Diseases; Genetic Diseases, Inborn; Congenital, Hereditary, and Neonatal Diseases and Abnormalities; Deaf-Blind Disorders; Deafness; Hearing Loss; Hearing Disorders; Ear Diseases; Otorhinolaryngologic Diseases; Hearing Loss, Sensorineural; Sensation Disorders; Neurologic Manifestations; Nervous System Diseases; Blindness; Vision Disorders; Abnormalities, Multiple; Congenital Abnormalities; Signs and Symptoms; Pathological Conditions, Signs and Symptoms

Study Design

• Study Type: interventional
• Phase: phase 3
• Allocation: RANDOMIZED
• Masking: QUADRUPLE
• Who Masked: PARTICIPANT, CARE PROVIDER, INVESTIGATOR, OUTCOMES ASSESSOR
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: INDUSTRY
• Responsible Party: SPONSOR

Study Record Dates

• First Submitted: December 16, 2025
• First Posted: December 18, 2025
• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): December 1, 2028
• Study Completion (Estimated): December 1, 2028
• Last Updated: December 18, 2025

Record last verified: 2025-12