SOUTH SAN FRANCISCO, Calif., April 17 /PRNewswire-FirstCall/ -- Cell
Genesys, Inc. (Nasdaq: CEGE) today reported immune response data from two
previously conducted Phase 2 clinical trials of GVAX immunotherapy for
prostate cancer. Evaluation of antibody responses in patients with advanced
prostate cancer from these studies shows that the GVAX cell-based
immunotherapy induces antibody responses to a broad array of prostate cancer-
associated antigens, including some not previously known to be associated with
prostate cancer. In addition, the antibody responses to this non patient-
specific product were predominantly patient-specific and unique from patient
to patient, indicating the potential advantage of a cell-based multi-antigen
product such as GVAX to generate the broadest and most relevant immune
response. Serological analysis of gene expression (SEREX) technology was also
used to identify target antigens involved in response to the immunotherapy.
More than 148 proteins to which antibody responses were induced were
identified and many of these proteins had not been identified previously as
prostate cancer-associated antigens. These findings were presented today by
Dr. Thomas Harding and colleagues from Cell Genesys at the annual meeting of
the American Association for Clinical Research being held in Los Angeles, CA.
GVAX immunotherapy for prostate cancer is currently being studied both as
a single agent and in combination with docetaxel chemotherapy in two Phase 3
clinical trials targeted to enroll approximately 1200 patients with metastatic
hormone-refractory prostate cancer (HRPC). This ongoing Phase 3 program is
supported by the median survival results from two, independent, multi-center
Phase 2 clinical trials. Cell Genesys recently reported final, updated
results from its second multi-center Phase 2 trial of GVAX immunotherapy for
prostate cancer, which evaluated escalating doses of the immunotherapy in 80
patients with metastatic hormone-refractory prostate cancer (HRPC).
Additional follow-up of the 22 patients who received the dose that is
comparable to that being employed in the company's ongoing Phase 3 program
revealed that their median survival is 35.0 months. Four patients have
withdrawn consent to further follow-up and thus were censored in the analysis.
The company also has previously reported final median survival results from
its first multi-center Phase 2 trial of GVAX immunotherapy for prostate cancer
in 34 patients with metastatic HRPC that showed an overall median survival of
26.2 months. The survival results from the two, independent multi-center
Phase 2 clinical trials compare favorably to the previously published median
survival of 18.9 months for metastatic hormone-refractory prostate cancer
patients treated with Taxotere(R) (docetaxel) chemotherapy plus prednisone,
the current standard of care for these patients. The company's ongoing Phase
3 program is designed to confirm this potential survival benefit of GVAX
immunotherapy for prostate cancer.
"The immune response data reported today provide added support for the
concept that a whole-cell immunotherapy, such as GVAX immunotherapy for
prostate cancer, is an ideal multi-antigen source that is capable of eliciting
an immune response to a broad array of tumor-associated antigens," stated
Peter K. Working, Ph.D., senior vice president of Research and Development at
Cell Genesys. "That the majority of antibody responses are unique to
individual patients is further evidence that the non patient-specific format
of GVAX immunotherapies is capable of inducing unique, patient-specific immune
responses. Moreover, the fact that many of these antigens have not before
been associated with prostate cancer, further suggests that a multivalent
antigen immunotherapy like GVAX immunotherapy may provide the best potential
for inducing an effective anti-tumor immune response, especially for
heterogeneous cancers such as prostate cancer."
Evidence of patient-specific immune responses associated with non patient-
specific GVAX immunotherapy products has also been reported in other cancers.
In August 2004, the company reported on data published in the Journal of
Experimental Medicine from a Phase 1 clinical trial of GVAX immunotherapy for
pancreatic cancer that provided evidence that patient-specific immune
responses can be generated following treatment with this non patient-specific
product. The article described detailed analyses of the immune response to
the immunotherapy in three out of 14 patients who were long-term survivors and
who also demonstrated strong T cell responses to mesothelin, a tumor-
associated protein found in the majority of pancreatic cancers and in the GVAX
immunotherapy for pancreatic cancer cells. The specificity of the T cell
response to mesothelin was shown to be unique to each responding patient
providing further scientific proof-of-concept for the company's GVAX
GVAX immunotherapy for prostate cancer is comprised of two prostate cancer
cell lines that have been modified to secrete GM-CSF (granulocyte-macrophage
colony stimulating factor), an immune stimulatory hormone, and irradiated for
safety. GVAX cancer immunotherapy for prostate cancer is being developed as a
non patient-specific, "off-the-shelf" pharmaceutical product.
Cell Genesys is focused on the development and commercialization of novel
biological therapies for patients with cancer. The company is currently
pursuing two clinical stage product platforms -- GVAX(TM) cancer
immunotherapies and oncolytic virus therapies. Ongoing clinical trials
include Phase 3 trials of GVAX immunotherapy for prostate cancer, Phase 2
trials of GVAX immunotherapies for pancreatic cancer and for leukemia, and a
Phase 1 trial of CG0070 oncolytic virus therapy for bladder cancer. Cell
Genesys continues to hold an equity interest in its former subsidiary,
Ceregene, Inc., which is developing gene therapies for neurodegenerative
disorders. Cell Genesys is headquartered in South San Francisco, CA and has
its principal manufacturing operation in Hayward, CA. For additional
information, please visit the company's website at www.cellgenesys.com.
Statements made herein about the company, other than statements of
historical fact, including statements about the company's progress, results
and timing of clinical trials and preclinical programs and the nature of
product pipelines are forward-looking statements and are subject to a number
of uncertainties that could cause actual results to differ materially from the
statements made, including risks associated with the success of clinical
trials and research and development programs, the regulatory approval process
for clinical trials, competitive technologies and products, patents,
continuation of corporate partnerships and the need for additional financings.
For information about these and other risks which may affect Cell Genesys,
please see the company's Annual Report on Form 10-K for the year ended
December 31, 2006 filed on March 1, 2007 as well as Cell Genesys' reports on
Form 10-Q and 8-K and other reports filed from time to time with the
Securities and Exchange Commission. The company assumes no obligation to
update the forward-looking information in this press release.
Contact: Ina Cu
SOURCE Cell Genesys, Inc.
/CONTACT: Ina Cu, Investor Relations of Cell Genesys, Inc.,
/Web site: http://www.cellgenesys.com
CO: Cell Genesys, Inc.
IN: HEA BIO
SU: TRI TDS
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7462 04/17/2007 07:00 EDT http://www.prnewswire.com