Positive preliminary findings have been reported from Phase I and Phase 2 clinical research using retinal pigment epithelial (RPE) cells derived from embryonic stem cells. The studies have indicated that patients with AMD and Stargardt’s may have early signs of vision gain following the stem cell treatment. Dr. Eyal Banin, from Hadassah-Hebrew University Medical Centre, Jerusalem, speaking at the American Academy of Ophthalmology Meeting, stated, “we are encouraged by the results thus far but this is just a first step in the long road towards making regenerative cell therapy a reality in macular and retinal degeneration.”
The novel research involved harvesting human embryonic stem cells from which RPE cells were obtained in vitro, prior to sub-retinal injection of either 50,000 or 200,000 cells into the retina of patients with retinal degeneration. Dr Ninel Z. Gregori, Bascom Palmer Eye Institute, Miami, Florida, participated in the study recruiting 13 dry AMD patients and 13 Stargardt’s disease patients. According to reports from the AAO Meeting, patients with poor visual acuity (defined as ≤ 20/400) received between 50,000 and 200,000 RPE cells, while patients with relatively better vision (defined as ≤ 20/100) received up to 100,000 RPE cells. In addition to the experimental therapy, a regimen of systemic immunosuppression was initiated for all patients 1 week before transplantation in order to maximise survival of the delivered cell population and minimise any immune response. Up to four years following administration of the RPE cells it was reported that there had been no cases of tumor formation, vitritis, macular edema, secondary glaucoma, retinal detachment, adverse pre-retinal RPE cell engraftment, vascular occlusion, photophobia, or any obvious immune rejection issues. Although the study was not powered for efficacy, researchers reported increased visual improvements in treated eyes. In one patient alone, Dr. Gregori reported that visual acuity had improved from a baseline of 19 letters at the start of the study to 38 letters, showing an acuity improvement from 20/500 to 20/200. In addition, NEI-VFQ-25 measurements reported a clinically meaningful improvement.
Significant commercial interest persists in the field of stem cell therapy however, the discipline is subject to increasing regulation from both the FDA and EMA in order to protect both patient safety and data integrity. The increased regulation has been welcomed by both clinicians and patients. EURETINA will continue close coverage of these technologies and trials over coming months as a number of clinical initiatives are scheduled to report findings from patient studies.