News Release

Fifth Clinical Trial Program for GRN163L

MENLO PARK, Calif., August 7, 2008 - Geron Corporation (Nasdaq: GERN) today announced the enrollment of the first patient in a clinical trial of its telomerase inhibitor drug, GRN163L, in locally recurrent or metastatic breast cancer.

The primary objective of the Phase I/II, dose escalation study is to determine the safety, maximum tolerated dose (MTD) and objective response rate of GRN163L when administered intravenously in combination with a paclitaxel/bevacizumab regimen in this patient population.

"We are excited to have enrolled the first patient in this study," said Kathy D. Miller, M.D., Associate Director for Clinical Research at the Indiana University Melvin and Bren Simon Cancer Center and lead investigator of the trial. "We have anticipated the clinical evaluation of this drug in breast cancer based on promising preclinical studies."

"This is an important milestone in the clinical development of our lead anti-cancer drug," said Fabio Benedetti, M.D., Geron's chief medical officer, oncology. "Extending the clinical testing of GRN163L to breast cancer reflects the potentially broad and important role of telomerase in fighting cancer."

The current study is the fifth clinical trial of GRN163L. Studies are ongoing at 14 other U.S. medical centers in patients with chronic lymphoproliferative diseases, multiple myeloma, non-small cell lung cancer, and other solid tumor malignancies administering GRN163L as either a single agent or in combination with conventional treatments. More information about these trials can be found in the Patient Information section of Geron's website at www.geron.com or on the NIH clinical trials registry at www.clinicaltrials.gov (search "GRN163L").

About Breast Cancer

Breast cancer is the most frequently diagnosed cancer in women, with an estimated incidence in the United States of more than 180,000 new cases and over 40,000 deaths this year. In addition, about 2,000 cases of breast cancer are expected to occur in men, accounting for 1% of all new breast cancers.

A regimen of paclitaxel and bevacizumab is a current standard treatment for metastatic breast cancer. Paclitaxel is an anti-mitotic agent used as a standard chemotherapy drug. Bevacizumab is a monoclonal antibody against vascular endothelial growth factor (VEGF) used in combination with standard chemotherapy for the treatment of multiple metastatic cancers.

About Telomerase and GRN163L

Telomerase is a critical and potentially broadly applicable tumor target. The enzyme is expressed in a wide range of malignant tumors, and its activity is essential for the indefinite replicative capacity of cancer cells that enables their malignant growth. Telomerase is absent or expressed only transiently at low levels in most normal adult tissues.

GRN163L is a short chain oligonucleotide that binds with very high affinity and specificity to the catalytic site of telomerase, resulting in competitive inhibition of enzyme activity. Proprietary manufacturing chemistry and 5' lipid chain were developed to improve the molecule's ability to penetrate cells and tissues.

GRN163L has demonstrated preclinical anti-tumor effects in a wide range of hematological and solid tumor models, including breast cancer.

Geron is a biopharmaceutical company that is developing first-in-class therapeutic products for the treatment of cancer and chronic degenerative diseases, including spinal cord injury, heart failure and diabetes. The products are based on our core expertise in telomerase and human embryonic stem cells. 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 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 June 30, 2008.

CONTACT:

Anna Krassowska, Investor and Media Relations, 650-473-7765, info@geron.com

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