The results of the study show that photoreceptors, the key cells of the eye involved in vision, were protected from degeneration following transplantation of HuCNS-SC cells into the Royal College of Surgeons (RCS) rat. The RCS rat is a well-established model of retinal disease which has been used extensively to evaluate potential cell therapies. Moreover, the number of cone photoreceptors, which are responsible for central vision, remained constant over an extended period, consistent with the sustained visual acuity and light sensitivity observed in the study. In humans, degeneration of the cone photoreceptors account for the unique pattern of visual loss in dry AMD.
"These results are the most robust shown to date in this animal model," said Dr. Lund, one of the study's lead investigators. "One of the more striking findings is that the effect on vision was long-lasting and correlated with the survival of HuCNS-SC cells more than seven months after transplantation, which is substantially longer than other cell types transplanted into this same model. Also important, particularly for potential clinical application, was that the cells spread from the site of initial application to cover more of the retina over time. These data suggest that HuCNS-SC cells appear to be a well-suited candidate for cell therapy in retinal degenerative conditions."
Alexandra Capela, Ph.D., another of the study's investigators and a senior scientist at StemCells, commented, "This study showed that the HuCNS-SC cells persisted and migrated throughout the retina, with no evidence of abnormal cell formation, which supports our hypothesis of a single transplant therapeutic. With this research, then, we have shown that vision can be positively impacted with a simple approach that does not require replacing photoreceptors or the RPE cells. We look forward to investigating this promising approach in the clinic later this year."
Following the above announcement, the company, on February 2nd, announced that it received authorization from the U.S. Food and Drug Administration (FDA) for a Phase I/II clinical trial of the company's proprietary HuCNS-SCr product candidate (purified human neural stem cells) in dry age-related macular degeneration (AMD), the most common form of AMD.
AMD is the leading cause of vision loss and blindness in people over 55 years of age, and approximately 30 million people worldwide are afflicted with the disease. There are no approved treatments for dry AMD.
"With the approval of this trial, we have accomplished something truly unique in the stem cell field, which is the extension of clinical testing of our proprietary human neural stem cell platform to all three elements of the central nervous system: the brain, spinal cord and eye," said Martin McGlynn, President and CEO of StemCells, Inc. "The preclinical data supporting our IND is particularly compelling and we look forward to getting this trial underway."
The Phase I/II trial will evaluate the safety and preliminary efficacy of HuCNS-SC cells as a treatment for dry AMD. The trial will be an open-label, dose-escalation study, and is expected to enroll a total of 16 patients. The HuCNS-SC cells will be administered by a single injection into the space beneath the retina. Patients' vision will be evaluated using conventional methods of ophthalmological assessment at predetermined intervals over a one-year period. Patients will then be followed for an additional four years in a separate observational study.
Editor’s Notes: The company has not as yet disclosed where the clinical trial will be held. But, since the pre-clinical work was done at Casey Eye (OHSU), my guess is that that's where the clinical trial will be carried out. When the company does announce this information, I will pass it along to you.
When Stem Cells Inc. does begin its clinical trial, it will be joining two other companies that have approved clinical trials using stem cells underway to treat dry AMD: Advanced Cell Technology and Centecor/J&J. ACT has Phase I/II trials underway at two U.S. sites, while awaiting approval for a site in London, while Centecor also has a Phase I/II trial underway at two U.S. sites.
For more information on these and other stem cell clinical trials, request my table, Stem Cell Therapy in Ophthalmology by Application.