ABOUT GRNOPC1

Executive Summary
Geron has received clearance from the U.S. Food and Drug Administration of its Investigational New Drug (IND) application for acute spinal cord injury using GRNOPC1. The clearance enables Geron to move forward with the world's first clinical study of a therapy derived from human embryonic stem cells (hESCs).

GRNOPC1 contains hESC-derived oligodendrocyte progenitor cells with demonstrated properties for remyelination and stimulation of nerve growth that lead to restoration of function in animal models of acute spinal cord injury.

Preclinical safety studies of GRNOPC1 have shown: no evidence of tumor formation 12 months after injection of clinical grade GRNOPC1 into the injured spinal cords of rats and mice; the absence of significant migration of the injected cells outside the spinal cord; and the absence of increased neuropathic pain, systemic toxicity or increased mortality in animals receiving GRNOPC1. In vitro studies have shown that GRNOPC1 is minimally recognized by the human immune system, which allows a clinical trial design that incorporates a limited course of low-dose immunosuppression and provides the rationale for an off-the-shelf, allogeneic cell therapy.

For the clinical program, Geron plans to initiate a Phase I multi-center trial that is designed to establish the safety of GRNOPC1 in patients with "complete" American Spinal Cord Association (ASIA) grade A subacute thoracic spinal cord injuries. Patients who will be eligible for the trial must have documented evidence of functionally complete spinal cord injury with a neurological level of T3 to T10 spinal segments and agree to have GRNOPC1 injected between seven and 14 days after injury.

GRNOPC1 is produced using current Good Manufacturing Practices (cGMP) in Geron's manufacturing facilities.

The production and commercialization of GRNOPC1 is protected by a portfolio of intellectual property rights owned by or exclusively licensed to Geron.

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. Geron is also the world leader in the development of human embryonic stem (hESC) cell-based therapeutics. The company has received FDA clearance to begin the world's first human clinical trial of a hESC-based therapy: GRNOPC1 for acute spinal cord injury. For more information, visit www.geron.com.

This backgrounder 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 backgrounder 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, 2008.