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patients have withdrawn consent to further follow-up and thus were censored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 immunotherapy strategy.
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 http://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
Investor Relations
650-266-3200
SOURCE Cell Genesys, Inc.
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Related links:
http://www.cellgenesys.com/
CONTACT:
Ina Cu, Investor Relations of Cell Genesys,
Inc., +1-650-266-3200
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