Restoring central vision with the PRIMA implant for photoreceptor degeneration

Restoration of Central Vision With the PRIMA Products in Patients With Photoreceptor Degeneration

This trial will test whether a small PRIMA implant can restore limited central vision in adults with inherited photoreceptor degeneration such as Stargardt disease or retinitis pigmentosa.

Quick facts

• Phase: NA
• Study type: Interventional
• Enrollment: 5 (estimated)
• Ages: 18 Years and up
• Sex: All
• Sponsor: Science Corporation (industry)
• Locations: 1 site (Sydney, New South Wales)
• Trial ID: NCT07266584 on ClinicalTrials.gov

What this trial studies

The PRIMA system is a small subretinal implant designed to bypass lost photoreceptors and stimulate remaining retinal cells to produce visual perception. Eligible adults will receive the PRIMA Stim implant in the study eye and undergo scheduled visual function and functional vision tests at defined follow-up timepoints. The investigation builds on prior clinical use of PRIMA in patients with geographic atrophy where it was reported to be safe and effective. Data from this study will be used to support continued development and regulatory evaluation of the device for people with inherited macular photoreceptor loss.

Who should consider this trial

Good fit: Adults aged 18 or older with confirmed inherited retinal degeneration affecting the macula in both eyes, very poor central acuity (about 20/320 or worse), and an atrophic macular patch large enough to accommodate the implant are ideal candidates.

Not a fit: Patients with damage to the optic nerve or retinal ganglion cell layers, those without the required macular atrophy size, or those with significant uncorrected ocular conditions (for example certain cataracts) are unlikely to benefit.

Why it matters

Potential benefit: If successful, the PRIMA implant could restore limited central vision and improve everyday tasks such as reading or face recognition for people who have lost photoreceptors.

How similar studies have performed: PRIMA has been tested in 38 patients with geographic atrophy and was reported to be both safe and effective in that population, but its use in inherited retinal degenerations remains exploratory.

Eligibility criteria

Inclusion Criteria:

1. Is 18 years or older at the date of inclusion;
2. Has a confirmed diagnosis of inherited retinal degeneration with the macula affected in both eyes;
3. The study eye has best corrected visual acuity of logMAR 1.2 (20/320) or worse as measured by ETDRS test;
4. Has an atrophic patch in the study eye including the fovea of at least the implant size (\>4.5 mm2 and \>2.4 mm in minimum diameter);
5. Understands the constraints of the study and accepts to present for all scheduled follow-up visits;
6. Signed the informed consent.

Exclusion Criteria:

1. 1\. Has cataract in the study eye (with LOCS III scale NO, NC, C or P\>1); (these patients will need to have cataract surgery performed prior to completion of baseline testing; all other patients will get IOL replacement during the PRIMA Stim implantation);
2. Underwent intraocular lens implantation in the study eye within the last month prior to enrolment (this corresponds to 4 weeks or 28 days) ;
3. Has an implanted IOL in the study eye and a refraction of the study eye outside of -4D; +4D limit (this criterion is not relevant for phakic eyes)
4. Has a highly myopic study eye (\>26 mm AP);
5. Has no light perception in either eye;
6. Has a history of documented choroidal neovascularization in either eye;
7. Has any signs of exudative AMD including exudative AMD with detachment of retinal pigment epithelium in the central visual field of the study eye;
8. Has an implanted telescope in one eye;
9. Has a black IOL in the study eye;
10. Has any disease (other than study allowed diseases) or condition that affects retinal function of the study eye or the visual system (e.g., central retinal artery/vein occlusion, end-stage diabetic retinopathy, Proliferative Diabetic Retinopathy (PDR), diabetic macular oedema (DME), severe Non-Proliferative Diabetic Retinopathy (NPDR), retinal detachment, infectious or inflammatory retinal disease, severe glaucoma, optic neuropathy, etc.) ;
11. Has any disease or condition that prevents adequate examination (including Optical Coherence Tomography (OCT)) of the study eye including but not limited to media opacities that cannot be resolved prior to implantation. Note, that this criterion is also important for the function of the implant;
12. Has a corneal endothelial cell count of less than 1000 cells/mm² in the study eye;
13. Suffers from nystagmus or other ocular motility disorders;
14. Has any disease or condition that precludes the understanding or communication of the informed consent, study requirements or test protocols (e.g., deafness, severe multiple sclerosis, amyotrophic lateral sclerosis, severe neuritis, etc.);
15. Has uncontrolled epileptic seizures;
16. Has a known sensitivity to the contact materials of the implant (iridium oxide, silicon-carbide and titanium);
17. Has a known allergy to anaesthetic drugs;
18. Presents with hypotonia in the study eye (\<8 mmHg);
19. Presents with hypertonia in the study eye (\>23 mmHg with treatment);
20. Has active cancer or a history of intraocular, optic nerve or brain cancer and metastasis;
21. Is an immune-suppressed participant (e.g., due to HIV positive diagnosis, etc.);
22. Is a known carrier of multi-resistant microorganisms;
23. Is receiving anticoagulation therapy that cannot be adapted to allow eye surgery;
24. Is participating in another investigational drug or device study that may interfere with the PRIMAlia study;
25. Has a history of chronic or recurrent infection or inflammation that would preclude participation in the study;
26. Has significant recurrent or chronic inflammations or infections. Specifically, patients with the following disorders are excluded:

    * Severe chronic and consuming diseases that frequently associated with infection (e.g. Crohn disease, Whipple's disease);
    * Active inflammation in the area of the eye (e.g. herpes of cornea and/or conjunctiva, recurrent blepharoconjunctivitis, hordeolum, chalazion);
27. Has a severe psychological disorder;
28. Does not have the mental capacity to legally sign the informed consent;
29. Has severe renal, cardiac, hepatic, etc. organ diseases (ASA IV or worse);
30. Has head dimensions that are incompatible with the PRIMA Companion glasses;
31. Has too high and/or unrealistic expectations (e.g., believes that a benefit is guaranteed or expects normal vision after surgery).
32. Physical constraints making use of PRIMA or rehabilitation impossible
33. Participant who, in the opinion of the investigator, is not suitable for participation in the study

Where this trial is running

Sydney, New South Wales

• Sydney Eye Hospital — Sydney, New South Wales, Australia (RECRUITING)

Study contacts

• Study coordinator: Ralf Hornig, PhD

Conditions: Stargardt Disease, Retinitis Pigmentosa, Inherited Retinal Degeneration