NEWARK, Calif.—StemCells, Inc. reported positive interim results from its Phase 1/2 clinical trial of the company's proprietary HuCNS-SC® human neural stem cell platform in dry age-related macular degeneration (AMD) at the 12th annual meeting of the International Society for Stem Cell Research (ISSCR) in Vancouver, Canada.
Interim trial results show a 65 percent reduction in the rate of geographic atrophy (GA) in the study eye when compared to the expected natural history of the disease as well as a 70 percent reduction in the rate of GA when compared to the control eye. “We are very, very excited,” says Stephen Huhn, M.D., FACS, FAAP, vice president, CNS clinical research and chief medical officer at StemCells, Inc. The eye has many unique attributes, Huhn notes. It provides a simple means of administering the therapy and the scale of the disease is simple to measure with a change of a few square centimeters making the difference. By treating one eye in each individual, with the other eye serving as the control, results were straightforward.
GA is the progressive loss of two important retinal tissue layers, the photoreceptors and the retinal pigmented epithelium. This degeneration is the cause of vision loss in dry AMD. Interim results also indicate improvements in visual function, as measured by the ability to distinguish shades of light versus dark, also referred to as "contrast sensitivity." This measure was improved in four of the seven patients and remained stable in the other three patients.
The interim analysis is based on a minimum follow up of at least 6 months and demonstrates a favorable safety profile for administration of the HuCNS-SC cells into the sub-retinal space of the study eye. "The interim data are very encouraging from two separate perspectives. First, the reduction in the rate of geographic atrophy suggests the HuCNS-SC cells are affecting the underlying cause of AMD. Secondly, the data demonstrates there are increases in contrast sensitivity, which is a vital aspect of visual function," said Huhn. "Impacting the progression of GA and enhancing visual function could have a very meaningful impact on the quality of life for AMD patients and the results to date strongly support our plans to initiate a randomized, controlled, Phase 2 proof-of-concept trial later this year."
"These interim results have exceeded our expectations at this stage of the trial," said David Birch, Ph.D., chief scientific and executive officer of the Retina Foundation of the Southwest in Dallas, Texas. "These results are particularly interesting given that the first cohort of patients had significant visual impairment and baseline GA. The next cohort of patients will have less impairment and we look forward to learning even more as we analyze data from the patients in the second half of the trial."
An estimated 10 million people in the United States either have age-related macular degeneration or are at substantial risk for receiving the diagnosis, according to the Foundation Fighting Blindness. AMD, a degenerative retinal disease that typically strikes adults in their 50s or early 60s and gradually progresses to destroy central vision, is the leading cause of blindness in adults over 55 years of age in the developed world. AMD refers to a loss of photoreceptors (rods and cones) from the macula, the central part of the retina. Approximately 85-90 percent of AMD cases are the "dry" type of the disease, the advanced form of which is referred to as "geographic atrophy."
The Phase 1/2 trial evaluates the safety and preliminary efficacy of HuCNS-SC cells as a treatment for dry AMD. Patients with dry AMD had to have evidence of GA to be eligible for inclusion. The investigation is divided into two sequential cohorts. Subjects are enrolled into each cohort based on best-corrected visual acuity (BCVA), as determined by the Electronic Early Treatment Diabetic Retinopathy Study (E-ETDRS) acuity test. Patients with BCVA of less than or equal to 20/400 in the study eye were enrolled in Cohort I. Patients with less severe BCVA of 20/320 to 20/100 in the study eye are being enrolled in Cohort II. Cohort I consists of four subjects who were each transplanted with 200,000 stem cells, followed by four subjects who have each been transplanted with 1 million cells. Cohort II will consist of eight subjects who will undergo transplant with 1 million cells. The HuCNS-SC cells are administered by a single injection into the space behind the retina in the most affected eye. Huhn notes that the cellular transplant approach could be a one-time intervention in contrast to antibody drug therapy.
Patients' vision is being evaluated using both conventional and advanced state-of-the-art methods of ophthalmological assessment. Evaluations are being performed at predetermined intervals over a one-year period to assess safety and signs of vision improvement. Patients will be followed for an additional four years in a separate observational study.
StemCells, Inc. has demonstrated human safety data from completed and ongoing clinical studies of its proprietary HuCNS-SC cells. StemCells clinicians and scientists believe that HuCNS-SC cells may have broad therapeutic application for many diseases and disorders of the central nervous system (CNS). Because the transplanted HuCNS-SC cells have been shown to engraft and survive long-term, there is the possibility of a durable clinical effect following a single transplantation. The Company's preclinical research established that HuCNS-SC cells can be directly transplanted in the CNS with no sign of tumor formation or adverse effects. The HuCNS-SC platform technology is a highly purified composition of human neural stem cells that are expanded and stored as banks of cells.
StemCells, Inc. is engaged in the research, development and commercialization of cell-based therapeutics and tools for use in stem cell-based research and drug discovery. The company's platform technology, HuCNS-SC® cells (purified human neural stem cells), is currently in clinical development as a potential treatment for a broad range of central nervous system disorders. The company is conducting a Phase 1/2 clinical trial in chronic spinal cord injury in Switzerland, Canada and the United States, and has reported positive interim data for the first eight patients. In a Phase 1 clinical trial in Pelizaeus-Merzbacher disease, a fatal myelination disorder in children, the company has shown preliminary evidence of progressive and durable donor-derived myelination in all four patients transplanted with HuCNS-SC cells. In addition, the company is pursuing preclinical studies in Alzheimer's disease, with support from the California Institute for Regenerative Medicine. StemCells also markets stem cell research products, including media and reagents, under the SC Proven® brand.
