Research Update

Positive Interim Findings for Geographic Atrophy Therapy.

Geographic Atrophy, also referred to as dry Age-related Macular Degeneration is a progressive retinal condition which primarily affects the central region of the eye, called the macula. It is characterised by the damage and death of photoreceptor cells; cells which detect incoming light into the eye and deliver information to the brain so images can be formed, and the retinal pigment epithelium (RPE) cell-layer, which nourishes and promotes the longevity of these photoreceptor cells. The degeneration of these cells results in a gradual decline in central visual acuity and the formation of blind spots and visual distortion, whereby straight lines can appear wavy.

Currently, no treatment or cure is available for Geographic Atrophy. However, positive interim results from a phase 1/2 clinical trial presented at the virtual Association for Vision Research in Ophthalmology (ARVO) indicate that transplanting healthy RPE cells grown outside the body (In-vitro) may be a promising strategy to improve visual acuity in people living with the condition and delay its onset¹.

In this study, human embryonic stem-cells; cells which have the capacity to grow into a variety of different cell-types, were specifically programmed to make RPE cells and subsequently delivered into the back of the eye via injection.

Three patient cohorts consisting of 12 patients had very poor vision and large Geographic Atrophy, while dosing of the fourth and final cohort of people with less severe visual impairments and smaller Geographic Atrophy is still ongoing.

Christopher D. Riemann, MD, who presented this research at the virtual ARVO meeting, highlighted that participants in the first three cohorts have not experienced any further vision loss following treatment intervention. While therapy is still being administered to cohort 4, improvements have been recorded to best corrected visual acuity, with treated participants successfully reading between 10 to 22 extra letters on the Snellen eye chart¹.

Dr. Riemann also remarked on structural changes to treated eyes, including a reduction in drusen; a yellow substance which accumulates beneath the retina and an early indicator of Geographic Atrophy, and “subretinal pigmentation and hyperreflective areas which suggest the presence and durability of the transplanted RPE cells”¹. These findings are strongly indicative of the promise of this stem-cell therapy to provide long-term success for treating Geographic Atrophy.

To date, transplantation of these stem-cell derived retinal pigment epithelium cells has been well tolerated in this clinical trial and poses as a novel way to treat and manage Geographic Atrophy and dry Age-related Macular Degeneration, although follow-up with the final cohort and other patients will be required to ensure the safety and efficacy of this treatment protocol.

References:

1. Riemann CD, et al. Phase I/IIa clinical trial of human embryonic stem cell (hESC)-derived retinal pigmented epithelium (RPE, OpRegen) transplantation in advanced dry form age-related macular degeneration (AMD): interim results. Presented at: Association for Research in Vision and Ophthalmology meeting; May 6, 2020 (virtual meeting).
2. ARVO Journal. Phase I/IIa Clinical Trial of Human Embryonic Stem Cell (hESC)-Derived Retinal Pigmented Epithelium (RPE, OpRegen) Transplantation in Advanced Dry Form Age-Related Macular Degeneration (AMD): Interim Results. Available at https://iovs.arvojournals.org/article.aspx?articleid=2745401. Accessed June 2020.