MENLO PARK, Calif.--(BUSINESS WIRE)--April 1, 2003--Geron Corporation (Nasdaq:GERN - News) announced today the publication of research results that describe the production of hepatocytes, the basic functional cells of the liver, from human embryonic stem cells (hESCs). The studies demonstrate that cells with multiple characteristics of hepatocytes, including drug-metabolizing enzyme activity, can be reproducibly differentiated from hESCs. These cells have potential for widespread use in drug discovery research as well as for transplantation therapy for patients with liver failure.
As published in the March issue of Cell Transplantation, Geron scientists describe protocols that differentiate hESCs into human hepatocytes that express albumin, alpha-1-antitrypsin, glycogen and other proteins found in human adult liver cells. Importantly, the cells also express certain Phase 1 and Phase 2 drug-metabolizing enzymes which are responsible for metabolizing most pharmaceuticals.
A reliable source for the production of human hepatocytes with well-characterized and reproducible properties would have a major beneficial impact on the drug discovery process. Currently, drug candidates are tested for toxicity and metabolic effects on the liver late in the discovery process using tools and methods that are inadequate. For example, access to primary human liver tissue is very limited, and hepatocytes isolated from adult liver tissue cannot be propagated in tissue culture. The available rat and mouse models only approximate human metabolism, and biochemical assays based on liver microsomes do not represent the complete physiological environment of liver cells. The widespread availability of standardized, normal human hepatocytes produced on a large scale from hESCs would allow drug metabolism and toxicity studies to be performed earlier in the drug discovery process, enabling the elimination of toxic compounds before undertaking costly human trials.
"This discovery serves as a foundation for the commercialization of hESC-based cell types for drug discovery applications," stated Thomas B. Okarma, Ph.D., M.D., Geron's president and chief executive officer. "Both large pharmaceutical companies and small biotechs would benefit from the availability of hepatocytes derived from hESCs that can reliably represent a functioning liver. We have already received two U.S. patents covering hESC-derived hepatocytes and their use as drug screening tools (U.S. Patent Nos. 6,458,589 and 6,506,574). Our next steps are to complete the characterization of these cells and to develop a high volume production process. At that point we have a product."
In addition to the hepatocytes described in this publication, Geron has generated six other cell types from hESCs that are being developed into therapeutic products: hematopoietic progenitors, dopaminergic neurons, oligodendrocytes, cardiomyocytes, beta islet cells and osteoblasts. All cell types exhibit normal functions expected of that cell type if isolated from adult tissue. The company is currently conducting pre-clinical animal safety and efficacy studies with four of these cell types. |
