Geron Announces Data on the Effects of Its Cancer Drug, GRN163L, on Multiple Myeloma at the American Society of Hematology Annual Meeting.

MENLO PARK, Calif. -- Geron Corporation (Nasdaq:GERN) announced today positive data from studies of its telomerase inhibitor drug, GRN163L, in animal models of human multiple myeloma and in tissue culture experiments with primary CLL patient cells. GRN163L is currently in a Phase 1-2 clinical trial in patients with chronic lymphocytic leukemia (CLL).

The multiple myeloma results, from two independent laboratories, were presented in a talk by Masood Shammas, Ph.D., a member of Dr. Nikhil Munshi's group at the Dana Farber Cancer Institute, and in a poster session by Server Ertem, a member of Dr. Malcolm Moore's group at the Memorial Sloan-Kettering Cancer Center.

Data on effects of GRN163L in primary CLL cells was generated in the laboratory of Nicholas Chiorazzi, Ph.D., at the North Shore - Long Island Jewish Research Institute, an affiliate of North Shore - Long Island Jewish Medical Center, one of the clinical sites participating in the GRN163L Phase 1-2 CLL clinical trial, and was published in abstract form at the meeting.

GRN163L Drives Human Multiple Myeloma Cells to Undergo Apoptotic Cell Death and Reduces or Prevents Myeloma Growth in Mice

Data presented by the Munshi laboratory showed (1) dose and time-dependent drug uptake, (2) telomerase inhibition and (3) apoptotic cell death in two different human myeloma cell lines after exposure to low micromolar concentrations of GRN163L. These effects were accompanied by telomere length reduction and a high frequency of myeloma cells with telomere-free ends, confirming the effect of telomerase inhibition on reducing telomere length. A mismatch control oligo had no effect on myeloma cells in vitro.

GRN163L treatment of mice bearing human bone fragments and inoculated with fluorescence-labeled human myeloma cells resulted in significant reduction or prevention of tumor growth in vivo and a statistically significant improvement in survival. This model mimics how multiple myeloma grows in vivo in human bone.

GRN163L as Single Agent and in Combination with Melphalan or Velcade(TM) Significantly Inhibits Cutaneous and Disseminated Myeloma Tumor Growth In Vivo

Data generated by the Moore laboratory using a myeloma cell line in a subcutaneous mouse model showed significant tumor growth inhibition with GRN163L alone and enhanced anti-tumor activity when used in combination with Melphalan. In a separate study using the same model, GRN163L in combination with Velcade(TM) significantly reduced tumor growth using a dose of Velcade(TM) that had no anti-tumor activity alone. A third study using a mouse model of disseminated myeloma showed significant reduction in tumor mass with GRN163L alone, and in combination with Velcade(TM). In all three studies, GRN163L was well tolerated.

GRN163L Inhibits Telomerase in Patient CLL Cells

In vitro data generated by the Chiorazzi laboratory using primary CLL cells obtained from patients demonstrated uptake of GRN163L into both cytoplasmic and nuclear compartments and effective inhibition of telomerase in patient CLL cells.

"We and our collaborators continue to demonstrate broad anti-tumor activity of GRN163L both in vitro and in vivo, alone and in combination with other anti-tumor agents," said Calvin Harley, Ph.D., Geron's chief scientific officer. "Of particular significance is the increased anti-tumor activity seen when GRN163L is used in combination with other anti-tumor agents that is unaccompanied by increased toxicity. These results support the potential clinical utility of GRN163L, alone or in combination, in patients with multiple myeloma and the drug's potential as a pan-cancer therapy."

Geron is a biopharmaceutical company focused on developing and commercializing three groups of products: i) therapeutic products for oncology that target telomerase; ii) pharmaceuticals that activate telomerase in tissues impacted by senescence, injury or degenerative disease; and iii) cell-based therapies derived from its human embryonic stem cell platform for applications in multiple chronic diseases.

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 Geron's telomerase inhibitor drug, GRN163L, 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, 2005.