Reduction in Residual Leukemic Cells Following Vaccination
ORLANDO, Fla., May 16 /PRNewswire-FirstCall/ -- Cell Genesys, Inc.
(Nasdaq: CEGE) today reported follow up clinical data from an ongoing Phase 2
trial of GVAX(R) vaccine for acute myelogenous leukemia (AML). Patients with
newly diagnosed leukemia were treated with chemotherapy, and if responsive,
subsequently received autologous bone marrow stem cell transplantation and
GVAX(R) vaccine for leukemia. The ongoing findings of this trial indicate
that vaccine therapy is generally well tolerated and may reduce residual
leukemic cells that persist after chemotherapy, as indicated by decreased
levels of WT-1, a leukemia-associated genetic marker, which is detectable in
over 95 percent of patients with active AML. In addition, there was an
observed correlation between relapse-free survival, decreased WT-1 and the
vaccine-associated immune response. These follow-up trial results were
reported at the American Society of Clinical Oncology (ASCO) Annual Meeting in
Orlando, FL, by Dr. Ivan Borrello from Johns Hopkins University, Baltimore, MD
(ASCO Abstract #6539).
The Phase 2 trial was conducted at four leukemia bone marrow transplant
centers in the United States and enrolled 54 patients. To date, 28 patients
have initiated GVAX(R) vaccination after achieving a complete response to
chemotherapy and thus far 21 of these patients have completed the stem cell
transplantation and initiated a series of post-transplant vaccinations. The
majority of patients had detectable WT-1 levels in their blood following
chemotherapy, indicating persistent leukemic cells. There were post-
vaccination declines in WT-1 in 11 of 16 patients (69%) in the blood and in 12
of 20 (60%) in the bone marrow after just a single pre-transplant vaccination.
In addition, two-year relapse-free survival was greater in the 11 patients who
showed a decrease in WT-1 in the blood following the single pre-transplant
vaccination compared to those who did not (73% vs. 0%, log-rank p=0.03) and
was also greater in the 19 patients who achieved an undetectable level of WT-1
in the blood following stem cell transplantation and further vaccination
compared to the six patients who did not (89% vs. 17%, log-rank p=0.002).
Finally, all six patients who mounted a vaccine-associated immune response, as
measured by induction of a delayed-type hypersensitivity reaction to their own
leukemic cells, have remained in complete remission from 16 to 29 months post
transplant and all six of these patients have had a vaccine-associated WT-1
decline or undetectable levels at the time of vaccination. To date, there
have been no serious side effects considered related to the vaccine therapy.
"We are encouraged by the results of our ongoing Phase 2 study of GVAX(R)
vaccine in acute leukemia, particularly the observed correlation between
vaccine-associated immune response, WT-1 response and relapse-free survival,"
stated Joseph J. Vallner, Ph.D., president and chief operating officer of Cell
Genesys. "We believe that GVAX(R) vaccine for leukemia represents a potential
new treatment option for acute leukemia that may be particularly important to
consider for elderly patients and patients for whom bone marrow
transplantation is not readily available or indicated."
The form of GVAX(R) vaccine used in this leukemia clinical trial is a non
patient-specific GVAX(R) product manufactured at Cell Genesys that is mixed at
the treatment center with the patient's irradiated tumor cells that were
collected prior to chemotherapy. Cell Genesys believes that this product
could potentially be developed as an off-the-shelf pharmaceutical for use in
multiple types of hematologic malignancies. Future manufacturing of the
product would be expected to occur at the company's plant in Hayward,
California, which has Phase 3 and potential market launch production
capabilities.
Clinical trials of GVAX(R) cancer vaccines are under way for multiple
types of cancer including prostate cancer, lung cancer, pancreatic cancer,
leukemia and myeloma. Cell Genesys' GVAX(R) cancer vaccines are whole-cell
vaccines which are designed to stimulate an immune response against the
patient's tumor. The vaccines are comprised of tumor cells that have been
irradiated and genetically modified to secrete GM-CSF (granulocyte-macrophage
colony stimulating factor), an immune stimulatory hormone that plays a key
role in stimulating the body's immune response to vaccines.
Cell Genesys is focused on the development and commercialization of novel
biological therapies for patients with cancer. The company is pursuing two
clinical-stage cancer product platforms -- GVAX(R) cancer vaccines and
oncolytic virus therapies. Clinical trials of GVAX(R) cancer vaccines include
an ongoing Phase 3 trial of GVAX(R) vaccine for prostate cancer as well as
trials of GVAX(R) vaccines for lung cancer, pancreatic cancer, leukemia and
myeloma. Clinical programs of oncolytic virus therapies include CG7870 for
prostate cancer and CG0070 for bladder cancer. Cell Genesys continues to hold
equity interests in its two former subsidiaries -- Abgenix, Inc., an antibody
products company and Ceregene, Inc., which is developing gene therapies for
neurodegenerative disorders. Cell Genesys is headquartered in South San
Francisco, CA and has manufacturing operations in San Diego, CA, Hayward, CA
and Memphis, TN. For additional information, please visit the company's
website at http://www.cellgenesys.com.
Statements made herein about the company and its subsidiaries, 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, 2004 dated March 14, 2005 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
Cell Genesys, Inc.
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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