Geron Corporation (Nasdaq:GERN) today provided additional comments on the recent clinical hold on its Spinal Cord Injury IND.

As biologic therapeutics advance in clinical trials, it is common practice to optimize product characteristics, improve manufacturing efficiency and scale, and to test the product in multiple disease models. As part of these ongoing efforts at Geron with respect to GRNOPC1, various animal studies were, and continue to be, performed to characterize the product’s effects in vivo. In previous animal studies of GRNOPC1 using materials that passed release specifications, a very low frequency of injected animals developed microscopic cysts in the regenerating injury site. These cysts were non-proliferative, confined to the injury site, and had no adverse effects on the animals. No animals developed teratomas or any other ectopic structure. Cysts of much larger size appear in the spinal cord scar tissue of up to 50% of patients with spinal cord injury.

A just completed animal study showed a higher frequency of cysts, although their characteristics were similar to the cysts seen in previous studies: non-proliferative, confined to the injury site, smaller than the injury cavity and not associated with adverse clinical outcomes.

As part of our ongoing product improvement efforts, new candidate markers and assays for product release have been identified that are linked with cyst formation across all animal studies in which cysts were found. Importantly, a manufactured lot of GRNOPC1 that was assessed using these markers and assays showed no cysts in another recently concluded animal study in spinal cord injured rats.

We have submitted these data to the FDA and are in discussions with the agency to answer its questions and proceed with the clinical trial. We are committed to the optimization of all our hESC-based products as we improve the manufacturing process and identify improved product release criteria.

About Geron

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 in different cancers. 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 June 30, 2009.