Stem Cells in Ophthalmology Update 4: ACT Receives FDA Approval to Use hESCs to Treat Dry AMD
Age-Related Macular Degeneration has two predominant forms, wet and dry. Dry AMD is the most common form, accounting for almost 90% of all cases. The progress of dry AMD includes a breakdown or thinning of the layer of RPE cells in the patient's macula, the region at the center of the retina responsible for high acuity vision. Over time, the progressive loss of RPE cells and accompanying loss of photoreceptors can cause severe vision loss and even blindness.
"ACT is now the first company to receive FDA clearance for two hESC trials, and is now a true translational leader in the field of regenerative medicine," said Gary Rabin, Interim Chairman and CEO of ACT. "It marks a major step forward, not just within the stem cell sector, but, potentially for modern healthcare techniques. We plan to proceed into the clinic with both of our hESC-based programs as quickly as possible." (For both dry AMD and for treating Stargardt’s Disease, approval for which was obtained in November 2010.)
The Phase I/II trial will be a prospective, open-label study that is designed to determine the safety and tolerability of the RPE cells following sub-retinal transplantation into patients with dry AMD. Twelve patients will be enrolled in the study at multiple clinical sites. Sites currently under consideration are the Jules Stein Eye Institute at UCLA, and the Ophthalmology Department at Stanford University School of Medicine. Additional sites may be considered.
"Dry AMD is the leading cause of blindness in individuals over the age of 55," stated Robert Lanza, MD, ACT's Chief Scientific Officer. "As the population ages, the incidence of AMD is expected to double over the next 20 years, further exacerbating this unmet medical need. Using our clinical-grade hESC lines, we are able to generate a virtually unlimited and reproducible supply of healthy RPE cells. Because only a small number of cells (50-200K) are needed to treat each patient, manufacturing and distribution of the therapeutic product is scalable with many similarities to the drug businesses that pharmaceutical companies understand well. Based on our animal model studies, we are very excited about the opportunity to treat patients. In a rat model of macular degeneration, we have seen a remarkable improvement in visual performance over untreated animals, without any adverse effects. We have also maintained near-normal function in a mouse model of Stargardt's Disease, a form of juvenile macular degeneration. In addition to this trial, we plan to concurrently use our RPE cells in our Phase I/II Clinical Trial for Stargardt's Disease, which received the green light from the FDA in November. We hope to see a similar benefit in both Stargardt's Disease and Dry AMD patients."
ACT's dry AMD therapeutic program uses RPE cells derived from hESCs to replace the lost RPE cells in the patient's eyes. ACT's proprietary RPE cell manufacturing process is protected by a number of broad patents, as is the use of hESC-derived RPE cells for treating macular degeneration. While the initial portion of the clinical trial will focus on safety, in subsequent clinical trials the company hopes to demonstrate that the RPE cells injected into the retinal space will be capable of slowing or halting progression of the disease, and potentially even restoring some visual acuity to patients.
"It is estimated that over ten million Europeans suffer from Age-Related Macular Degeneration, representing a vast unmet need and a significant market opportunity," commented Edmund Mickunas, ACT's Vice President of Regulatory Affairs. "We are moving ahead aggressively to seek regulatory clearance from the European Medicines Agency to conduct clinical trials in Europe."