Geron Receives U.S. Patent Covering Use of Telomerase Inhibitors in Patients.

Business Editors/Health/Medical Writers

BIOWIRE2K

MENLO PARK, Calif.--(BUSINESS WIRE)--April 15, 2003

Geron Corporation (Nasdaq:GERN) announced today that it has been granted U.S. Patent No. 6,548,298, by the U.S. Patent and Trademark Office, with claims directed to

"Geron was the first to clone the RNA component of human telomerase," noted David J. Earp, J.D., Ph.D., Geron's vice president of intellectual property, "and we have previously been granted patents for that RNA and oligonucleotide compounds based on its sequence. This latest patent is a significant addition to our portfolio because it explicitly covers the use of those oligonucleotides to treat patients. The Patent Office sets a high hurdle for claims to methods of treating patients -- in this case we were able to submit data showing the efficacy of these oligonucleotides against a number of different types of human tumors in animal models."

GRN163 is a potent, specific and non-toxic inhibitor of telomerase in cancer cells. The drug is a short (13 base) oligonucleotide made using proprietary chemistry that confers stability and enhanced cellular uptake to the compound. The drug is active against all major human tumor types in vitro and in animal models of human brain, prostate, lymphoma, myeloma and cervical cancers. Unlike most anti-cancer drugs, GRN163 has not caused toxicity in animals at therapeutically effective doses. The compound is now undergoing IND-enabling GLP toxicology studies and, depending on results, the company expects to file an IND with the FDA for the treatment of glioblastoma (brain cancer).

Geron is a biopharmaceutical company focused on developing and commercializing therapeutic and diagnostic products for applications in oncology and regenerative medicine, and research tools for drug discovery. Geron's product development programs are based upon three patented core technologies: telomerase, human embryonic stem cells and nuclear transfer.

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 future applications of Geron Corporation's technology constitute forward-looking statements involving risks and uncertainties, including, without limitation, risks inherent in the development and commercialization of potential products, need for additional capital, need for regulatory approvals or clearances, and the 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 annual report on Form 10-K for the year ended on December 31, 2002.