StemCells announced the results of a four-year observation study in patients with neuronal ceroid lipofuscinosis, or NCL, also referred to as Batten disease, who had been transplanted with the Company's proprietary HuCNS-SC cells, or purified human neural stem cells, in the initial Phase I study. Key results include long-term evidence of safety, up to five years post transplantation, for the surgical transplantation of the HuCNS-SC cells into multiple sites in the brain and at doses of up to one billion cells. The study results represent the first, and thus far only, multi-year data set following transplantation of neural stem cells into human subjects, and supports the feasibility of the company's approach in multiple neurological disorders. Six patients were enrolled in the Company's Phase I clinical study in Batten disease. All six were transplanted with HuCNS-SC cells and followed for twelve months after transplantation. Five patients completed the Phase I study and subsequently enrolled in a four-year, long-term observational study, with three of the five surviving to the end of the four-year study. The long-term clinical data appear to be consistent with the natural history of the disease and conclusions about impacting the disease course cannot be made in an open-label trial. The reported adverse events are consistent with the underlying disease and there have been no safety concerns attributed to the HuCNS-SC cells. Magnetic resonance imaging scans of the brain show progressive atrophy consistent with the patient's neuropsychological performance. Quality-of-life measures remained stable across all three surviving patients.