Ophthalmology · Clinical trials
Retinitis Pigmentosa Clinical Trials
Approved therapies, the pivotal-trial endpoints they were judged on, the magnitude of benefit — and the drugs that failed their endpoints, and why.
Indication overview
About retinitis pigmentosa — and why its trials are hard
Retinitis pigmentosa (RP) is a group of inherited retinal dystrophies causing progressive rod and cone photoreceptor degeneration, leading to night blindness, constricting peripheral fields, and eventual central vision loss. It is genetically heterogeneous, with mutations in dozens of genes and autosomal dominant, recessive, and X-linked inheritance. For most genetic subtypes there is no approved disease-modifying drug; management centers on low-vision aids, vitamin A considerations in select cases, and genetic counseling. The landmark exception is voretigene neparvovec (Luxturna), approved by the FDA in 2017 as the first directly administered gene therapy for a genetic disease in the United States. It treats confirmed biallelic RPE65 mutation-associated retinal dystrophy, which includes some RP and Leber congenital amaurosis phenotypes, and does not treat RP caused by other genes. An implanted retinal prosthesis (Argus II) was previously available for late-stage RP but has been discontinued. Numerous gene, cell, and optogenetic therapies are in trials for other RP genotypes.
Approved therapies & pivotal evidence
What's been approved — and by how much it moved the endpoint
| Drug (brand) | Approved | Setting | Pivotal trial | Primary endpoint | Magnitude of benefit |
|---|---|---|---|---|---|
| Voretigene neparvovec (Luxturna) | 2017 | One-time subretinal AAV2 gene therapy for confirmed biallelic RPE65 mutation-associated retinal dystrophy (only this genotype) | Phase 3 randomized controlled trial (Russell et al., Lancet 2017) | Change in bilateral multi-luminance mobility test (MLMT) score at 1 year | Treated group improved a mean of ~1.8 light levels on the MLMT versus ~0.2 in controls (statistically significant), with gains in functional vision and light sensitivity. |
Where trials have failed
Drugs that missed their endpoint — and what contributed
The most instructive lessons in retinitis pigmentosa development come from programmes that failed the endpoint that mattered.
| Drug / trial | Endpoint outcome | What contributed |
|---|---|---|
| Ciliary neurotrophic factor (CNTF) encapsulated cell implant (NT-501/renexus) — CNTF for RP randomized trials (Neurotech, sponsored studies) | Did not produce a significant, sustained improvement in visual acuity or visual field in RP; failed to meet efficacy endpoints for RP | Neuroprotective effect insufficient to halt photoreceptor degeneration; some measures showed reduced function despite structural changes. |
Choosing the right endpoint
Primary endpoints that matter in retinitis pigmentosa trials
- Multi-luminance mobility test (MLMT) — Navigational course at varying light levels; the pivotal functional-vision endpoint for Luxturna.
- Full-field light sensitivity threshold (FST) — Measures retinal light sensitivity; a secondary endpoint sensitive to RPE65 therapy effect.
- Visual field / kinetic perimetry — Tracks the characteristic peripheral field constriction central to RP disability.
- Best-corrected visual acuity (BCVA) — Often relatively preserved until late RP, limiting its sensitivity as a primary endpoint.
How iNGENū runs retinitis pigmentosa trials
Physician-led design, built for FDA submission
Endpoint & biomarker strategy
Board-certified specialists design endpoints and patient selection aligned to current FDA guidance for this indication.
FDA-ready data
Built to ICH-GCP and 21 CFR 312.120, with direct FDA submission — data accepted by the FDA, EMA and MHRA.
Faster, lower-cost delivery
~4-week ethics via the TGA CTN scheme, up to 43.5% R&D rebate, and 80–90% below US CRO cost.
Request a fixed-milestone proposal and a tailored endpoint & feasibility summary for this indication.
Frequently asked questions
Retinitis Pigmentosa clinical trials — FAQs
Is there a treatment for all forms of RP?
How do I know if Luxturna could help me?
Is Luxturna a cure?
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