Geron Initiates Clinical Trial of Telomerase Inhibitor Drug in Combination With Paclitaxel and Carboplatin in Patients With Non-Small Cell Lung Cancer.

Third Clinical Trial Program for 163L - First Clinical Use in Combination Chemotherapy

Ongoing Studies in CLL and Solid Tumors Continue to Accrue Patients

MENLO PARK, Calif. -- Geron Corporation (Nasdaq:GERN) announced today the initiation of a clinical trial of its telomerase inhibitor drug, GRN163L, in patients with advanced non-small cell lung cancer (NSCLC).

The primary objective of the Phase I/II study is to determine the safety and maximum tolerated dose of GRN163L when administered intravenously in combination with a standard paclitaxel/carboplatin regimen. This is the first time GRN163L is being clinically tested in combination with standard chemotherapy.

"We are excited to study GRN163L in lung cancer," said Joan Schiller, M.D., chief of the Division of Hematology and Oncology and deputy director of Simmons Comprehensive Cancer Center at the University of Texas Southwestern, who is the study's lead investigator. "There is a striking unmet need to improve survival in NSCLC. Telomerase is highly expressed in lung cancer, and preclinical data suggest activity of the drug as a single agent in preventing disease progression in animals bearing human lung cancer cells."

Alan Colowick, M.D., Geron's president, oncology, said, "This is an important milestone in the clinical development of GRN163L. The favorable tolerability and pharmacokinetics demonstrated so far in our solid tumor and CLL trials enable us to test our drug in combination with standard chemotherapy in patients for the first time. Moreover, the safety data generated in our other ongoing trials enable us to start dosing GRN163L in this trial at levels comparable to doses given in cohort 4 of the solid tumor and CLL trials. Once we have established the safety and dosing parameters of GRN163L in combination with paclitaxel and carboplatin in NSCLC, we can study the same combination in other tumor settings."

Geron's two ongoing clinical trials are sequential cohort, dose escalation studies designed to determine the safety and tolerability of GRN163L administered intravenously on a weekly basis as monotherapy to patients with refractory or relapsed CLL and patients with advanced solid tumors. Patients interested in enrollment into either of these ongoing trials should visit the Patient Information page of Geron's website at www.geron.com.

Lung cancer is the leading cause of cancer death worldwide, with an estimated incidence of more than 210,000 new cases in 2007. Non-small cell lung cancer represents more than 85% of these cases, and only 15% of patients with NCSLC survive five years.

About Telomerase and GRN163L

Telomerase is a broadly applicable and critical tumor target. It is expressed in a broad array of malignant tumors, essential for malignant cell growth and absent or expressed transiently at low levels in most normal adult tissues.

GRN163L, Geron's telomerase inhibitor drug, is a short chain oligonucleotide that is unique in its resistance to nuclease digestion in blood and tissues and its very high affinity and specificity for telomerase. The molecule has superior cellular and tissue penetration properties due to its proprietary manufacturing chemistry and its 5' lipid chain.

GRN163L has been demonstrated to have anti-tumor effects in a wide range of hematological and solid tumor models and appears to be unique in its observed effects on tumor stem cells - the rare, chemotherapy-resistant cancer cells that cause cancer recurrence.

Geron is developing first-in-class biopharmaceuticals for the treatment of cancer and chronic degenerative diseases, including spinal cord injury, heart failure, diabetes and HIV/AIDS. 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 such forward-looking statements in this press release regarding potential applications of GRN163L and Geron's telomerase 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 March 31, 2007.