Data Show Geron's Cell-Based Therapeutic for Spinal Cord Injury Survives and Exhibits Remyelination for at Least Nine Months Following Injection

Geron Corporation (Nasdaq:GERN) today announced that data show GRNOPC1, the company’s human embryonic stem cell (hESC)-based therapeutic for spinal cord injury, survives and exhibits durable and robust human remyelination in spinal cord-injured rats for at least nine months following a single injection. Presented by Geron’s Arjun Natesan, Ph.D., at the Society for Neurosciences Annual Meeting in San Diego, the data also demonstrate that GRNOPC1 does not amplify neuropathic pain or the reaction to painful stimuli. This finding is in contrast to research that shows many other cell types, when injected into the spinal cord, amplify neuropathic pain, a common long-term complication of spinal cord injury in man. "These important results speak to both the long-term safety and duration of effectiveness of GRNOPC1,” said Thomas B. Okarma, Ph.D., M.D., Geron’s president and CEO. "A comparison of the GRNOPC1-treated rats at nine months after injection against untreated control rats shows dramatic evidence of durable remyelination of intact rat axons traversing the lesion. These results show that a single injection of GRNOPC1 cells produces significant and persistent remyelination of the damaged spinal cord.” Allodynia, a painful response to a stimulus that normally does not elicit pain, was assessed on large numbers of GRNOPC1-treated and untreated spinal cord-injured rats at three, six, and nine months post-injury. Both mechanical and cold stimuli were repeatedly applied at the injury site and on the paws by observers blinded to the animals’ treatment. Measurements included vocalization, attendance to the stimulus site, and avoidance behaviors. GRNOPC1-treated animals exhibited no increase in allodynia or neuropathic pain compared to untreated spinal cord-injured animals at any time. GRNOPC1 is an allogeneic population of cells containing oligodendroglial progenitors that is intended for transplantation into the lesion site of patients with spinal cord injury to induce tissue repair. Geron’s development plan for the product calls for the filing of an Investigational New Drug (IND) Application with the U.S. Food and Drug Administration and, pending the agency’s review, initiation of human clinical trials in 2008. Geron is developing first-in-class biopharmaceuticals for the treatment of cancer and chronic degenerative diseases, including spinal cord injury, heart failure and diabetes. The company is advancing an anti-cancer drug and a cancer vaccine that target the enzyme telomerase through multiple clinical trials. Geron is also the world leader in the development of human embryonic stem cell-based therapeutics, with its spinal cord injury treatment anticipated to be the first product to enter clinical development. For more information, visit www.geron.com. 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 statements in this press release regarding potential applications of Geron’s human embryonic stem cell technology constitute forward-looking statements that involve risks and uncertainties, including, without limitation, risks inherent in the development and commercialization of potential products, uncertainty of clinical trial results or regulatory approvals or clearances, need for future capital, dependence upon 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, 2007.