Transplantation of retinal pigment epithelium (RPE) and photoreceptor progenitors (PRP) generated through a xeno-free unified protocol showed improved visual sensitivity in two rodent models

Abstract

Purpose : Age-Related Macular Degeneration (AMD) initiates as result of retinal pigment epithelium (RPE) dysfunction while Retinitis Pigmentosa (RP) is an inherited early-onset disease caused due to premature loss of photoreceptors/RPE or both. One promising therapeutic approach for both is to replace lost or damaged RPE/photoreceptors with allogeneic retinal cell suspension. The aim of this study was to test the safety and efficacy of our cryopreserved retinal cell therapy products.

Methods : We devised a unified GMP compliant protocol by faithfully recapitulating key milestones of retinogenesis for differentiation of RPE and photoreceptor progenitors (PRP) from human induced pluripotent stem cells (hiPSC). De novo generated RPE and PRP after freeze-thaw were characterized in-depth to validate their identity, purity and potency. Cryopreserved RPE and PRP-cell based products were used in RCS rats and NOD-SCID rd1 mice respectively to assess their safety and efficacy following subretinal injections.

Results : RPE (Eyecyte-RPE) and PRP (Eyecyte-PRP) expressed tight junction proteins, pigmentation as well as ciliation markers and neuro-retinal proteins and cone/rod markers respectively. RPE secreted polarization-related growth factors VEGF/PEDF whereas PRP responded to KCL induced polarization. mRNA sequencing demonstrated typical molecular signature of mature retinal tissue and absence of markers from undesired lineages. RPE transplantation salvaged visual function in RCS rats evidenced by optokinetic tracking (OKT) and photoreceptor rescue. PRP transplantation improved visual perception in NOD-SCID rd1 mice corroborated by light dark test and OKT; positive ERG results indicated functional photoreceptor activity in host ONL. No animals showed teratoma formation or any kind of ectopic growth in the eye.

Conclusions : Eyecyte-RPE and Eyecyte-PRP were found to be safe and efficacious in two different animal models mimicking early and late stage retinal degeneration. To our knowledge, this is the first demonstration of a unified GMP compliant scalable protocol showing strong animal efficacy and safety data for both AMD and RP. These findings provides robust proof-of-principle results for IND-enabling studies to test these potential allogeneic cell therapies in AMD and RP patients.

This is a 2020 ARVO Annual Meeting abstract.

 

ONL rescue at D90