Geron Corporation and Merix Bioscience Announce Study Results and Collaboration for Telomerase Cancer Immunotherapy.

Business Editors/Health & Medical Writers

MENLO PARK, Calif./RESEARCH TRIANGLE PARK, N.C.--(BW HealthWire)-- August 29, 2000

Geron Corporation (Nasdaq:GERN) and Merix Bioscience, Inc. announced today that researchers at Duke University Medical Center have demonstrated the use of telomerase as an antigen to stimulate an immune response that inhibits tumor growth in animals and kills human tumor cells in vitro. The research, published in the September 2000 issue of Nature Medicine, shows that RNA encoding the catalytic reverse transcriptase protein component of telomerase (TERT RNA), when introduced into dendritic cells, can stimulate the immune system to recognize and destroy telomerase-positive cancer cells. Geron and Merix also announced a collaboration to develop the telomerase-based cancer immunotherapy for clinical and commercial applications.

Eli Gilboa, Ph.D. and his colleagues at Duke developed the process of modifying dendritic cells ex vivo with RNA encoding tumor antigens as an immunotherapy against cancer. Dr. Gilboa, Dr. Johannes Vieweg and colleagues have now shown that this immunization strategy can be used to stimulate the body's immune system to kill telomerase-positive cancer cells. In this system, TERT RNA is introduced into dendritic cells ex vivo in tissue culture. Upon immunization, the TERT RNA-modified dendritic cells educate specialized killer cells known as cytotoxic T lymphocytes (CTLs) to recognize and destroy cancer cells expressing telomerase.

The research, performed by the Duke scientists in collaboration with scientists at Geron, takes advantage of the fact that telomerase is abnormally activated in most human cancers. Telomerase is detected in greater than 80% of human tumor samples tested, including those of breast, lung, colon, prostate and hematologic origin.

Study Results

In the reported studies, mouse TERT RNA-modified dendritic cells generated an in vivo immune response in mice that was effective in inhibiting the growth of breast, melanoma, and bladder cancer tumors.

The method was also tested in vitro with human cells obtained from patients with renal and prostate carcinomas. Human TERT (hTERT) RNA was introduced into dendritic cells which induced CTL responses that recognized and killed the patients' tumor targets in culture.

"The experimental results are important," commented Tom Okarma, Ph.D., M. D., president and chief executive officer of Geron. "Telomerase is universally present in cancer cells. Therefore, development of hTERT RNA as an antigen to elicit an immune response against a broad range of tumor types, either alone or in combination with other antigens, would represent a significant advance in cancer therapy."

"We are very pleased with the study results," added Dr. Gilboa. "The next steps are to conduct thorough preclinical safety studies and assess the clinical potential of this method."

Geron and Merix Collaboration

Geron and Merix will collaborate to assess the clinical and commercial potential of hTERT RNA as an antigen for cancer immunotherapy using Merix's delivery system. Each company brings unique proprietary assets to the collaboration. Geron has expertise and proprietary rights in the field of telomerase. Merix holds an exclusive license from Duke University for the ex vivo RNA-modified antigen-presenting cell (i.e., dendritic cell) technology developed by Dr. Gilboa. In addition, Merix, through its collaboration with Gilboa, has access to ex vivo dendritic cell processing expertise for production of the modified cells and immunological assay technologies to facilitate monitoring of a patient's immune response to treatment. The combination of the companies' technologies will allow Geron and Merix to jointly advance the development of this cancer immunotherapy platform.

Under the terms of the collaboration, Geron will sponsor preclinical studies at Duke to confirm the safety and efficacy of hTERT RNA-modified dendritic cells to mediate immune responses against tumors. Studies will be performed in parallel by Merix. Geron and Merix will jointly determine the clinical development plan for the combined technology platform. Financial terms of the agreement were not disclosed.

"This collaboration allows both companies to leverage technologies and resources to establish hTERT RNA as a safe and effective antigen in cancer immunotherapy," stated David Greenwood, senior vice president of corporate development and chief financial officer of Geron. "We can then proceed directly to human clinical development."

"Human telomerase-encoding RNA is an exciting antigen to bring together with our ex vivo RNA-modified dendritic cell technology platform," added John Irick, executive vice president of Merix. "This collaboration enables a focused effort to accelerate the potential realization of a new cancer therapy."

Geron is a biopharmaceutical company focused on discovering, 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 pluripotent stem cells and nuclear transfer.

Merix is a private immunotherapy company dedicated to the treatment of metastatic cancers and chronic infectious diseases. Merix is focused on discovering, developing, and commercializing autologous therapeutic immunotherapies and immunological monitoring products based on its proprietary platform for the modification of dendritic cells with the messenger RNA encoding target antigens.

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 product development and future applications of Geron's technology constitute forward-looking statements that involve risks and uncertainties, including, without limitation, risks inherent in the development and commercialization of potential products, our dependence on collaborative partners to perform their respective responsibilities, 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 quarterly report on Form 10-Q for the quarter ended June 30, 2000.

To receive an index and copies of recent press releases, call Geron's News On Demand toll-free fax service, 800/782-3279. Additional information about Geron Corporation can be obtained at http://www.geron.com.

Additional information about Merix Bioscience, Inc. can be obtained at http://www.merixbio.com.