Retinitis Pigmentosa (RP)Phase 3NCT07290530
24-Month Trial of NPI-001 for the Preservation of Photoreceptors in Retinitis Pigmentosa Associated With Usher Syndrome
A Phase 3 study testing N-acetylcysteine amide in people with Retinitis Pigmentosa (RP) and Usher Syndrome, run by Nacuity Pharmaceuticals, Inc..
Trial 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. Read more about this study
- Who is it for?
- Ages 18 years and older
- Conditions the study is for
- Retinitis Pigmentosa (RP), Usher Syndrome
- What is being tested?
- N-acetylcysteine amide
- Type of treatment
- Pill or oral medicine
- Could I receive a placebo?
- Yes, some participants may receive a placebo
- How many people
- 80 participants
- Where
- No sites listed yet
- Study dates
- Dec 2026to Jul 2029
- Phase
- Phase 3
- Are there results?
- Not yet: the study is under way
Key requirements
Who can take part, as listed by the sponsor. Only the study team can confirm whether you are eligible, so take this list to your doctor.
- Ages 18 years and older
- All sexes
- No healthy volunteers
- Adult, Older adult
Who may be able to join
- 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).
- 5. On stable dose of medications associated with other conditions for at least one month.
- 6. 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.
Who cannot join
- 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.
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- 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.
- Potential participant lives in the same household as a current participant in this study.
- Subjects who are willing or unable to refrain from donation of blood from 30 days prior to Screening, plasma from 2 weeks prior to Screening, or platelets from 6 weeks prior to Screening until 56 days following the last study drug dose administered.
- Inability to provide blood samples, including difficulty with venous access.
- Any reason, in the opinion of the Principal Investigator, the participant should not participate.
About this study
Official title: A 24-Month, Randomized, Double-Masked, Placebo-Controlled Trial of NPI-001 for the Preservation of Photoreceptors in Retinitis Pigmentosa Associated With Usher Syndrome
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
- Retinitis Pigmentosa (RP), Usher Syndrome
- Being tested
- N-acetylcysteine amide, Placebo
- Keywords
- N-acetylcysteine amide
- Medical subject headings
- Retinitis Pigmentosa, Usher Syndromes
What participants receive
What participants receive. In a randomised study each person is assigned to one group by chance.
N-acetylcysteine amideDrug
N-acetylcysteine amide (NPI-001) tablets (250 mg), taken BID
PlaceboOther
Placebo tablets, BID
| Study group | Role | What they receive |
|---|---|---|
| NPI-001 | Experimental | NPI-001 tablet, BID Receives: Drug: N-acetylcysteine amide |
| Placebo | Placebo comparator | Placebo tablet, BID Receives: Other: Placebo |
What is being measured
The primary outcome is the main question the study is designed to answer.
EZ Area Rate of Change
Measured: 24 months
Timeline
From the start of the study to its completion; the mark is today. Estimated dates are the sponsor’s plan.
- First posted18 Dec 2025
- Study startDec 2026 (estimated)
- Primary completionJul 2029 (estimated)
- Study completionJul 2029 (estimated)
Resources
- Official record on ClinicalTrials.govThe registry entry this page is built from, with its full change history.
- Other trials for Retinitis Pigmentosa (RP)Studies of the same condition, open and under way.
- What the trial phases meanHow a treatment moves from first tests in people to approval.
More details
For doctors and researchers: how the study is designed, who runs it, and its registry IDs.
Study design
- Study type
- Interventional
- Phase
- Phase 3
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind
- Who is masked
- Participant, Care provider, Investigator, Outcomes assessor
- Enrolment
- 80 participants (estimated)
Sponsor and investigators
- Lead sponsor
- Nacuity Pharmaceuticals, Inc.
- Sponsor type
- Industry (pharma, biotech, devices)
- Responsible party
- Sponsor
IDs, dates and publications
- ClinicalTrials.gov ID
- NCT07290530
- Sponsor's protocol ID
- C-24-01
- Status last verified
- Jun 2026
- First submitted
- 16 Dec 2025
- Last updated
- 1 Jul 2026
- Results posted
- No
- Data monitoring committee
- Yes
- FDA-regulated drug
- Yes
- FDA-regulated device
- No
- Individual data sharing
- No: There is no plan to share IPD, in accordance with data sharing described in the informed consent documents and protocol.
Study at a glance
From the registry record, last updated by the sponsor on 1 Jul 2026. Recruitment status is as the sponsor reported it: confirm with the study team.
- Official title
- A 24-Month, Randomized, Double-Masked, Placebo-Controlled Trial of NPI-001 for the Preservation of Photoreceptors in Retinitis Pigmentosa Associated With Usher Syndrome
- ClinicalTrials.gov ID
- NCT07290530
- Acronym / sponsor ID
- C-24-01
- Conditions
- Retinitis Pigmentosa (RP), Usher Syndrome
- Keywords
- N-acetylcysteine amide
- Phase
- Phase 3
- Study type
- Interventional
- Recruitment status
- Not yet recruiting
- Enrolment
- 80 participants (estimated)
- Lead sponsor
- Nacuity Pharmaceuticals, Inc.Industry (pharma, biotech, devices)
- Study start
- Dec 2026 (estimated)
- Primary completion
- Jul 2029 (estimated)
- Study completion
- Jul 2029 (estimated)
- First posted
- 18 Dec 2025 (actual)
- Results
- Not posted in the source record
Clinical summary
The research question as the sponsor registered it. This describes what the study plans to test, not what it found.
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
Study design
- Primary purpose
- Treatment
- Allocation
- Randomised
- Intervention model
- Parallel groups
- Masking
- Quadruple blind (participant, care provider, investigator, outcomes assessor)
- Number of arms
- 2
| Arm | Type | Receives |
|---|---|---|
| NPI-001 | Experimental | Drug: N-acetylcysteine amideNPI-001 tablet, BID |
| Placebo | Placebo comparator | Other: PlaceboPlacebo tablet, BID |
Who may qualify
- Ages
- 18 years and older
- Sex
- All
- Healthy volunteers
- Not accepted
- Age groups
- Adult, Older adult
Key inclusion criteria (7 listed)
- 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).
Key exclusion criteria (19 listed)
- 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.
Eligibility is decided by the study team after screening; this overview does not establish that a patient qualifies. Full inclusion and exclusion criteria.
Interventions
| Intervention | Type | Arms |
|---|---|---|
| N-acetylcysteine amideN-acetylcysteine amide (NPI-001) tablets (250 mg), taken BID | Drug | NPI-001 |
| PlaceboPlacebo tablets, BID | Other | Placebo |
Primary outcome
EZ Area Rate of Change
Time frame: 24 months
Results and safety
This study is still under way. Results are not available in the source record yet.
Research links
- Official record on ClinicalTrials.govLast updated by the sponsor 1 Jul 2026.
- Individual participant dataSharing planned: No. There is no plan to share IPD, in accordance with data sharing described in the informed consent documents and protocol.
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A 24-Month Trial of NPI-001 for the Preservation of Photoreceptors in Retinitis Pigmentosa Associated With Usher Syndrome
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Referral and contact
AzTrials does not enrol participants or take referrals. Contact the study team or a site listed below; they decide who can take part.
The record lists no contact. Use the official record to reach the sponsor.
Questions about this trial
What is this clinical trial studying?
A Phase 3 study testing N-acetylcysteine amide in people with Retinitis Pigmentosa (RP) and Usher Syndrome, run by Nacuity Pharmaceuticals, Inc..
The full registered description is in the About this study section and the official record.
Who may be eligible to take part?
The sponsor lists 7 inclusion and 19 exclusion criteria. Eligibility is decided by the study team after screening, so read the full criteria and contact a listed site.
Is this clinical trial currently recruiting?
The record says: opening soon, as of the sponsor's last update on 1 Jul 2026. Status can change between updates, so confirm with the study contact before making plans.
What are the possible benefits and risks?
They depend on the study and the treatment, and no study can promise a benefit. Some participants in this study may receive a placebo. The study team explains the known risks during informed consent, before anyone joins; the record itself does not list them.
What does this phase mean?
Phase 3 studies compare the treatment with the current standard treatment or a placebo in a large group, to confirm how well it works and watch for side effects.
Not every study follows the same path, and some studies (observational studies, device studies) have no phase.
Are results available for this study?
This study is still under way. Results are not available in the source record yet.
How can a doctor refer a patient or contact the research team?
The record lists no contact. The official record names the sponsor, who can be asked directly. AzTrials does not enrol participants or take referrals.
What does the primary outcome measure?
EZ Area Rate of Change (time frame: 24 months). It is what the study was designed to measure, not a finding.
Where can I read the original study information?
Does a listing mean the treatment is approved or proven to work?
No. A listing means the study is registered. It does not show that the treatment is safe, works, or is approved by a regulator.
How often is this information updated?
AzTrials copies changed records from ClinicalTrials.gov every night and reloads the whole registry every week. The sponsor last updated this record on 1 Jul 2026.