News Release

Geron Announces Studies Demonstrating That Cardiomyocytes Derived From Human Embryonic Stem Cells Engraft And Prevent Heart Failure In The Infarcted Rodent Heart

Menlo Park, CA – February 22, 2006 –– Geron Corporation (Nasdaq: GERN) announced today the presentation of studies showing that cardiomyocytes differentiated from human embryonic stem cells (hESCs) survive, engraft and prevent heart failure when transplanted into an infarcted rat heart. The results provide proof–of–concept that transplanted hESC–derived cardiomyocytes show promise as a treatment for myocardial infarction and heart failure.

The studies were reported at the meeting on Molecular Mechanism of Cardiac Disease and Regeneration (Santa Fe, New Mexico), and were performed by Drs. Michael LaFlamme, Charles Murry and colleagues at the University of Washington in collaboration with scientists at Geron Corporation. In these studies, cardiomyocytes were produced from hESCs and injected into the left ventricular wall of rats that had undergone reversible coronary ligation to produce myocardial infarctions. In one arm of the study, cardiomyocytes were injected with a combination of agents that increased their survival post transplantation. The hearts were examined one and four weeks after injection. Human cardiomyocytes had populated the infarcted myocardium at both time points. At the four week time point, all animals showed the presence of hESC–derived cardiomyocytes.

In another arm of the study, survival agents only – without cardiomyocytes – were administered to the rats. Comparative analysis at four weeks showed that animals that received both cells and survival agents had significantly improved heart function by echocardiography compared to animals that received survival agents alone.

The echo data showed that animals receiving cells had reduced left ventricular end systolic and end diastolic diameters demonstrating that the hESC–derived cardiomyocytes had decreased the degree of infarct–induced heart failure.

"The durable engraftment of the hESC–derived cardiomyocytes accompanied by the restoration of cardiac function in the animals that received cells provides further evidence for the feasibility of using these cells in myocardial repair," stated Jane S. Lebkowski, Ph.D., Geron’s senior vice president of regenerative medicine.

"There are over 5 million patients with congestive heart failure in the U.S. alone and each year over 800,000 Americans suffer a heart attack," said Thomas B. Okarma, Ph.D., M.D., Geron’s president and chief executive officer. "The studies reported today are the first to demonstrate survival of hESC–derived heart muscle cells in the infarcted myocardium that significantly improved cardiac function. These results are in contrast to studies by others using adult bone marrow–derived hematopoietic or skeletal myoblast stem cells which do not produce new cardiac muscle tissue after injection into infarcted hearts."

Geron is a biopharmaceutical company focused on developing and commercializing three groups of products: i) therapeutic products for oncology that target telomerase; ii) pharmaceuticals that activate telomerase in tissues impacted by senescence, injury or degenerative disease; and iii) cell–based therapies derived from its human embryonic stem cell platform for applications in multiple chronic diseases.

This news release may contain forward–looking statements made pursuant to the "safe harbor" provisions of the Private Securities Litigation Reform Act of 1995. Investors are cautioned that such forward–looking statements in this press release regarding potential applications of Geron’s hESC technology constitute forward–looking statements that involve risks and uncertainties, including, without limitation, risks inherent in the development and commercialization of potential products, need for future capital, dependence on collaborators and maintenance of our intellectual property rights. Actual results may differ materially from the results anticipated in these forward–looking statements. Additional information on potential factors that could affect our results and other risks and uncertainties are detailed from time to time in Geron’s periodic reports, including the quarterly report on Form 10–Q for the quarter ended September 30, 2005.

Contact:
Geron Corporation
David L. Greenwood
Chief Financial Officer
650–473–7765

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