Stem cells generally are self-renewing primitive cells that can develop into functional, differentiated cells. Human embryonic stem cells (hESCs), which are derived from very early stage embryos called blastocysts, are unique because:
they are pluripotent, which means they can develop into all cells and tissues in the body, and
they self-renew indefinitely in the undifferentiated state because they express high levels of telomerase.
The ability of hESCs to divide indefinitely in the undifferentiated state without losing pluripotency is a unique characteristic that distinguishes them from all other stem cells discovered to date in humans. We have demonstrated that hESCs express telomerase continuously, a characteristic of immortal cells. Other stem cells such as blood or gut stem cells express telomerase at very low levels or only periodically; they therefore age, limiting their use in research or therapeutic applications. hESCs can be expanded in culture indefinitely and hence can be banked for scaled product manufacture.
We intend to use human embryonic stem cell technology to enable the development of transplantation therapies by providing standard starting material for the manufacture of therapeutic cells and facilitate pharmaceutical research and development practices by providing cells for disease models and screening, and for assigning function to newly discovered genes.
We have developed proprietary methods to grow, maintain, and scale the culture of undifferentiated hESCs that use feeder cell-free and serum-free media with chemically defined components. Moreover, we have developed scalable processes to differentiate these cells into therapeutically relevant cells. We have developed cryopreserved formulations of hESC-derived cells to enable our business model of delivering "on demand" cells for therapeutic use. Under our collaboration with Corning Life Sciences, a division of Corning Incorporated, we are working together to develop synthetic growth surfaces to replace the biological surface coatings that are widely used today to grow hESCs.
We and our collaborators are testing six different hESC-derived therapeutic cell types in animal models. In five of these cell types we have demonstrated efficacy, as evidenced by durable engraftment or functional improvements of the treated animals. We are planning a clinical trial of GRNOPC1, our hESC-derived therapy targeted for the treatment of acute spinal cord injury. Click here for clinical trial information.
Geron's second hESC product, GRNCM1, is a population of cardiomyocytes, the contractile cells of the heart, which is intended for drug screening and the treatment of patients with myocardial disease. Geron also has made substantial progress in deriving pancreatic islet â cells for diabetes and dendritic cells for two applications, including cancer immunotherapy and graft acceptance (to prevent immune rejection of the other cell types used in therapeutic applications). With our collaborators in the United Kingdom at the University of Edinburgh, we are deriving osteoblasts for osteoporosis, chondrocytes for osteoarthritis and hepatocytes for liver failure and metabolism and toxicity testing of drug compounds. In 2008, the University of Edinburgh received a grant of £3.6 million from the UK Stem Cell Foundation, with funding from the Medical Research Council and Scottish Enterprise to conduct preclinical safety and efficacy studies in our collaboration.
Geron's hESCs were derived by our collaborators from donated in vitro fertilized blastocysts (very early-stage embryos). We currently have nine hESC lines; most of our development work so far has focused on three of those lines.
