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Safety and Efficacy of NPI-001 Tablets for RP Associated With Usher Syndrome (SLO RP)

The safety and scientific validity of this study is the responsibility of the study sponsor and investigators. Listing a study does not mean it has been evaluated by the U.S. Federal Government. Know the risks and potential benefits of clinical studies and talk to your health care provider before participating. Read our disclaimer for details.
ClinicalTrials.gov Identifier: NCT04355689
Recruitment Status : Recruiting
First Posted : April 21, 2020
Last Update Posted : November 18, 2022
Foundation Fighting Blindness
Information provided by (Responsible Party):
Nacuity Pharmaceuticals, Inc.

Brief Summary:
This study will examine the safety and efficacy of NPI-001 Tablets as compared to placebo for 24 months in subjects with vision loss due to RP associated with Usher syndrome.

Condition or disease Intervention/treatment Phase
Usher Syndromes Drug: NPI-001 Other: Placebo Phase 1 Phase 2

Detailed Description:
This study will examine the safety and efficacy of oral NPI-001 Tablets as compared to oral placebo tablets for 24 months in subjects with vision loss due to RP associated with Usher syndrome.

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Study Type : Interventional  (Clinical Trial)
Estimated Enrollment : 48 participants
Allocation: Randomized
Intervention Model: Parallel Assignment
Intervention Model Description: NPI-001 Tablets versus Placebo
Masking: Quadruple (Participant, Care Provider, Investigator, Outcomes Assessor)
Masking Description: Double-masked
Primary Purpose: Treatment
Official Title: Safety and Efficacy of NPI-001 Tablets Versus Placebo for Treatment of Retinitis Pigmentosa Associated With Usher Syndrome
Actual Study Start Date : September 3, 2020
Estimated Primary Completion Date : January 2025
Estimated Study Completion Date : January 2025

Arm Intervention/treatment
Experimental: NPI-001
NPI-001 Tablet, 250 mg, BID
Drug: NPI-001
oral tablet

Placebo Comparator: Placebo
Placebo Tablet, BID
Other: Placebo
Placebo tablets

Primary Outcome Measures :
  1. Evaluate change from baseline for retinal sensitivity assessed by microperimetry of active versus placebo [ Time Frame: 24 months ]
    Evaluate change from baseline for retinal sensitivity assessed by microperimetry of active versus placebo

Information from the National Library of Medicine

Choosing to participate in a study is an important personal decision. Talk with your doctor and family members or friends about deciding to join a study. To learn more about this study, you or your doctor may contact the study research staff using the contacts provided below. For general information, Learn About Clinical Studies.

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Ages Eligible for Study:   18 Years and older   (Adult, Older Adult)
Sexes Eligible for Study:   All
Accepts Healthy Volunteers:   No

Inclusion Criteria:

  1. Male or female, age ≥18 years.
  2. Able to comprehend and willing to sign an informed consent form (ICF) and to adhere to the study protocol.
  3. Diagnosed with Usher syndrome.
  4. EZ zone with width ≥500 microns, which includes the fovea in each eye at Visit 2, (Screen B).
  5. Have at least 20 detectable points on the MAIA grid.
  6. On stable dose of medications associated with other conditions for at least one month.
  7. 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, or vasectomy.

Exclusion Criteria:


  1. All edges of the EZ area in both eyes cannot be visualized at Visit 2 (Screen B).
  2. 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.
  3. Intraocular surgery within the last two months or capsulotomy within the last month.
  4. 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.
  5. Unstable fixation during microperimetry in either eye at either screening or baseline visits.


  6. Use of any other investigational new drug, or participation in another clinical trial within 12 weeks before the start of study treatment.
  7. 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.
  8. Liver or kidney disease, cystic fibrosis, asthma or chronic obstructive pulmonary disease (COPD), history of thrombocytopenia not due to a reversible cause, or other blood dyscrasia.
  9. Suspected liver dysfunction determined by having alanine aminotransferase (ALT), aspartate aminotransferase (AST), or bilirubin values > 1.5 X the upper limit of normal (ULN).
  10. Platelet or hemoglobin values that are below the lower limit of normal at screening (subjects with normal hemoglobin and mean corpuscular volume below the lower limit of normal should have iron studies performed to ensure that they are iron replete before taking part in the study), or neutrophils or white cell count which is above the upper limit of normal.
  11. Presence of more than + proteinuria on urinalysis at screening or (confirmed by abnormal albumin creatinine ratio).
  12. Presence of hematuria on urinalysis at screening. (If hematuria is detected on urinalysis, then the specimen should be subjected to microscopy, and subject should be excluded if more than 10 X 106 red blood cells/L.) If the subject is a female in whom the hematuria may be due to menses, then the urinalysis can be repeated after a few days.
  13. C-reactive protein (CRP) value above 10 mg/L.
  14. Subject has a recent history of presence of gross blood in stools.
  15. History of known sensitivity to N-acetylcysteine or similar thiol compounds.
  16. History of hypersensitivity to any medication or food resulting in systemic symptoms.
  17. History of cancer (other than non-melanoma skin cancer) diagnosed or requiring treatment within the past 2 years.
  18. 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.
  19. Lactating women who are breast-feeding.
  20. A potential participant lives in the same household as a current participant in this study.
  21. Inability to provide blood samples, including difficulty with venous access.
  22. Any reason, in the opinion of the Principal Investigator, the subject should not participate.

Information from the National Library of Medicine

To learn more about this study, you or your doctor may contact the study research staff using the contact information provided by the sponsor.

Please refer to this study by its ClinicalTrials.gov identifier (NCT number): NCT04355689

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Contact: Jami Kern, PhD +1-817-336-3000 info@nacuity.com
Contact: G. Michael Wall, PhD +1-817-336-3000 info@nacuity.com

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Queensland Eye Institute Recruiting
Brisbane, Australia
Contact: Research Manager         
CERA Recruiting
Melbourne, Australia
Contact: Research Manager         
Lions Eye Institute Recruiting
Perth, Australia
Contact: Research Manager         
Sydney Eye Hospital / Save Sight Institute Recruiting
Sydney, Australia
Contact: Research Manager         
Sponsors and Collaborators
Nacuity Pharmaceuticals, Inc.
Foundation Fighting Blindness
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Study Chair: Lee Anderson, MD Nacuity Pharmaceuticals, Inc.
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Responsible Party: Nacuity Pharmaceuticals, Inc.
ClinicalTrials.gov Identifier: NCT04355689    
Other Study ID Numbers: C-18-04
First Posted: April 21, 2020    Key Record Dates
Last Update Posted: November 18, 2022
Last Verified: November 2022
Individual Participant Data (IPD) Sharing Statement:
Plan to Share IPD: No

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Studies a U.S. FDA-regulated Drug Product: No
Studies a U.S. FDA-regulated Device Product: No
Keywords provided by Nacuity Pharmaceuticals, Inc.:
retinitis pigmentosa Usher vision NPI-001 tablet
Additional relevant MeSH terms:
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Usher Syndromes
Retinitis Pigmentosa
Pathologic Processes
Retinal Diseases
Eye Diseases
Eye Diseases, Hereditary
Retinal Dystrophies
Retinal Degeneration
Genetic Diseases, Inborn
Deaf-Blind Disorders
Hearing Loss
Hearing Disorders
Ear Diseases
Otorhinolaryngologic Diseases
Hearing Loss, Sensorineural
Sensation Disorders
Neurologic Manifestations
Nervous System Diseases
Vision Disorders
Abnormalities, Multiple
Congenital Abnormalities