Geron Announces Presentation at ECTRIMS/ACTRIMS October 25, 2011 3:38 PM ET Non-Clinical Data Supports Use of GRNOPC1 in Multiple Sclerosis MENLO PARK, Calif., October 25, 2011 - Geron Corporation (Nasdaq: GERN) today announced data on the use of GRNOPC1, oligodendrocyte progenitors derived from human embryonic stem cells, for myelin repair in a non-human primate model. The data supports further investigation of the potential therapeutic use of GRNOPC1 in central nervous system (CNS) disorders where the central or contributing pathology is destructive removal of myelin from nerve axons, such as observed in multiple sclerosis (MS), myelitis and spinal cord injury. GRNOPC1 is currently in a Phase 1 clinical trial in patients with spinal cord injury. The new data were presented at the 5th Joint Triennial Congress of the European and Americas Committees for Treatment and Research in Multiple Sclerosis, in Amsterdam, by Prof. Jeffery D. Kocsis, Ph.D., from Yale University School of Medicine. The work was performed in collaboration with scientists at Geron. The studies utilized a non-human primate model where demyelinated lesions, such as seen in multiple sclerosis, were induced chemically in the spinal cord. GRNOPC1 was injected into the demyelinated spinal cord lesions one week after chemical induction. The lesion sites from six monkeys were analyzed using light and electron microscopy at various timepoints up to one year after injection of GRNOPC1 to look for evidence of cell survival and remyelination of nerve axons. In the first few weeks after implantation, the injection sites contained maturing transplanted cells indicative of a premyelinating phenotype with evidence of variable numbers and degrees of remyelinated axons. By four months post implantation, GRNOPC1 had induced extensive and thick myelin around the formerly denuded axons. Human cells were detected at the lesion site, providing evidence for survival of transplanted GRNOPC1. There was no evidence of abnormal tissue, tumor formation or other pathologies associated with the injection of GRNOPC1. Neurological exams of the injected animals were normal. The data showed in the non-human primate that GRNOPC1 can survive at the lesion site and progressively promote remyelination of axons. "These new data confirm and extend previous results showing that GRNOPC1 can promote remyelination in rodents and non- human primates," said Jane Lebkowski, Ph.D., Geron's Chief Scientific Officer. "These results provide further support for the potential of GRNOPC1 to provide therapeutic benefit in a number of central nervous system diseases, such as MS and myelitis." About GRNOPC1 Oligodendrocytes produce myelin, an insulating layer made up of protein and fatty substances that forms around nerves in the CNS to enable them to conduct electrical signals. Without myelin, many of the nerves in the brain and spinal cord cannot function properly. Oligodendrocytes are lost in CNS disorders such as spinal cord injury and MS. GRNOPC1 contains hESC-derived oligodendrocyte progenitor cells that have demonstrated remyelinating, nerve growth stimulating and angiogenic properties leading to restoration of function in rodent models of acute spinal cord injury. Non-clinical studies have shown that administration of GRNOPC1 seven days after injury significantly improved locomotor activity and kinematic scores of rats with spinal cord injuries compared to untreated controls. Histological examination of the injured spinal cords treated with GRNOPC1 showed improved axon survival and extensive remyelination surrounding the rat axons. Geron is conducting a Phase 1 clinical trial to assess the safety of GRNOPC1 in patients with complete, thoracic spinal cord injuries. In addition, Geron has established collaborations with academic groups to evaluate GRNOPC1 in models of other CNS disorders. For more information about GRNOPC1, visit www.geron.com/GRNOPC1Trial. About Geron Geron is developing first-in-class biopharmaceuticals for the treatment of cancer and chronic degenerative diseases. The company is advancing anti-cancer therapies through multiple Phase 2 clinical trials in different cancers by targeting the enzyme telomerase and with a compound designed to penetrate the blood-brain barrier. The company is developing cell therapies from differentiated human embryonic stem cells, with the first product in a Phase 1 clinical trial for spinal cord injury. For more information, visit www.geron.com. Page 1/2 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 technologies and GRNOPC1 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 protection 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, filed with the Securities and Exchange Commission, including the quarterly report on Form 10-Q for the quarter ended June 30, 2011. CONTACT: Anna Krassowska, Ph.D. Investor and Media Relations 650-473-7765 [email protected] # # # Page 2/2.