Retinal Imaging in CNTF -Releasing Encapsulated Cell Implant Treated Patients for Early-stage Retinitis Pigmentosa
Condition: Retinitis Pigmentosa; Usher Syndrome Type 2; Usher Syndrome Type 3
MeSH terms: Usher Syndromes; Retinitis; Retinitis Pigmentosa; Syndrome
Intervention: NT-501; Sham
Intervention description: Study participants will undergo surgery to have an NT-501 Encapsulated Cell Therapy implant placed into the study eye.; Non-penetrating sham procedure to mimic implant procedure in the other eye.
Phase: Phase 2
Study type: Interventional
Primary purpose: Treatment
Allocation: Randomized
Intervention model: Parallel Assignment
Intervention model description: Participants are considered in screening upon signing of the consent. Enrollment does not occur until participant is deemed eligible, as per screening, and randomized for implant. As such, there were 22 total participants enrolled in the study. There was a participant who died prior to screening procedures being conducted of which was captured in the AE section as the death occurred after consent to enter screening period. However, this participant was not enrolled as they had not completed screening or randomization for implant.
Masking: Double (Participant, Investigator)
Enrollment: 22.0
Sex: All
Minimum age: 18 Years
Maximum age: 55 Years
Healthy volunteers: No
Keywords: Retinitis pigmentosa; Usher syndrome type 2; Usher syndrome type 3; Cone photoreceptor; Vision; Blind

Summary:

      This clinical trial is a single-site, 30 patient study for participants who have early stage
      retinitis pigmentosa, or Usher syndrome (type 2 or 3). Funding Source - FDA OOPD and
      Foundation Fighting Blindness.
    

Eligibility criteria:

        Inclusion Criteria:

          1. Participant must be between 18 and 55 years of age.

          2. Participant must have a diagnosis of retinitis pigmentosa or Usher Syndrome type 2 or
             3 (without profound deafness or cochlear implants).

          3. Participant must understand and sign the protocol informed consent. If the
             participant's vision is impaired to the point where he/she cannot read the informed
             consent document, the document will be read to the participant in its entirety.

          4. Best-corrected visual acuity must be no worse than 20/63 (at least 59 letters).

          5. Participants must have clear natural lenses.

          6. Participants must have less than 6 diopters myopia.

          7. Participants must be medically able to undergo ophthalmic surgery for the NT-501
             device insertion and able to undergo all assessments and tests associated with the
             protocol.

          8. Females of childbearing potential (women with last menses <1 year prior to screening)
             must agree to use an effective form of birth control from study onset until they
             complete the study.

          9. Participants must have reproducible baseline AOSLO image at 2 baseline imaging
             sessions with quality suitable to identify a minimum of 7 regions of interest (ROIs)
             at which reliable cone spacing and/or density measures can be made over the central
             5.7 degrees.

         10. Participants must have interocular symmetry of disease severity as measured by cone
             spacing, with a difference of less than 2 standard deviations in average cone spacing
             z-scores at the selected ROIs between the 2 eyes.

         11. Participant's clinical diagnosis must be consistent with retinal degeneration in the
             set of retinitis pigmentosa (RP) dystrophies.

        Exclusion Criteria:

          1. Participant is medically unable to comply with study procedures or follow-up visits.

          2. Participant who has any of the following lens opacities: cortical opacity > standard
             3, posterior subcapsular opacity > standard 3, or a nuclear opacity > standard 3 as
             measured on the AREDS clinical lens grading system; or participant is pseudophakic or
             aphakic.

          3. Participant has history of corneal opacification or lack of optical clarity.

          4. Participant has undergone LASIK surgery or other refractive surgery for either eye.

          5. Participant has nystagmus.

          6. Participant has greater than 6 diopters myopia.

          7. Participant has cystoid macular edema with cysts present within 4 degrees of the
             foveal center that prevent acquisition of at least 7 regions of interest with clear
             images of cone photoreceptors.

          8. Participant has fewer than 7 regions of interest (ROIs) present on 2 baseline AOSLO
             image montages.

          9. Participant has retinal vascular disease such as diabetic retinopathy or prior retinal
             vascular occlusive disease.

         10. Participant has chronic requirement (e.g., ≥4 weeks at a time) for ocular medications
             or has disease(s) that in the judgment of the examining physician are vision
             threatening, toxic to the lens, retina, or optic nerve or may affect the primary
             outcome.

         11. Participant has a requirement of acyclovir and/or related products during study
             duration. To be eligible for this study, the participant must discontinue use of these
             products prior to enrollment and must not continue with the products until after they
             have completed the study.

         12. Participant is receiving systemic steroids or other immunosuppressive medications.

         13. Participant is currently participating in or has participated in any other clinical
             trial of a drug by ocular or systemic administration within the last 6 months.

         14. Participant has previous exposure to an intra-ocular device or implant into the eye
             (excluding intra-ocular lens).

         15. Participant has uveitis or other retinal inflammatory disease.

         16. Participant has a history of myocardial infarction within the last 12 months.

         17. Participant is pregnant or lactating.

         18. Participant is considered immunodeficient or has a known history of HIV. A laboratory
             test for HIV will be performed, and a positive result is also an exclusion criterion.

         19. Participant with a history of ocular herpes zoster.

         20. Participant is on chemotherapy.

         21. Participant has a history of malignancy, except study participant with cancer treated
             successfully ≥5 years prior to inclusion in the trial.

         22. Participant with severe hearing disabilities in both ears.

         23. Participant who has been diagnosed and treated for amblyopia as an infant.

         24. Participant who, in the opinion of the study doctor, will not be a good study subject.