Research With Retinal Cells Derived From Stem Cells for Myopic Macular Degeneration

Pathologic myopia is a major cause of legal blindness worldwide. In myopic macular degeneration (MMD), there is degeneration of the retinal pigment epithelial (RPE) layer, and associated photoreceptors, resulting in vision loss. There is currently no standard treatment for MMD. Transplantation of intact sheets of RPE and suspensions of isolated individual RPE cells as well as autologous translocation of RPE cells has been attempted as treatment for AMD. Human photoreceptors are comprised of two cell types-rods and cones. Both have a close relationship with the outermost retinal cells, the retinal pigmented epithelium (RPE). The RPE is located between the choroid and the photoreceptors. The RPE maintains photoreceptor function by recycling photopigments,delivering, metabolizing and storing vitamin A, phagocytosing rod photoreceptor outer segments, transporting iron and small molecules between retina and choroid, maintaining Bruch's membrane and absorbing stray light to allow better image resolution. In essence, the RPE layer is critical to the function and health of photoreceptors and the retina as a whole. Human PRE (hRPE) transplantation may be a viable option for treatment of degenerative diseases of the retina. MA09-hRPE cells are fully differentiated human RPE cells derived from embryonic stem cells. Transplanted hRPE cells prepared by Advanced Cell Technology have been studied in rodent models of macular degenerative disease. The data suggests that the subretinal injection of ACT's hRPE cell products rescues, or at least delays, loss of visual function in two animal models of retinal degenerative diseases. The main purpose of this study is to evaluate the safety and tolerability of MA09-hRPE cellular therapy in patients with Myopic Macular Degeneration (MMD). Another objective is to evaluate potential efficacy endpoints to be used in future studies of RPE cellular therapy.