>>SOUTH SAN FRANCISCO, Calif., June 26 /PRNewswire-FirstCall/ -- Cell Genesys, Inc. (Nasdaq: CEGE - News) today presented clinical data from an exploratory Phase 2 clinical trial of GVAX® pancreatic cancer vaccine in patients with inoperable, metastatic pancreatic cancer. The company also updated the status of a parallel Phase 2 trial in patients with operable pancreatic cancer who receive the vaccine after surgery, an approach which continues to be the focus of the company's GVAX® pancreatic cancer vaccine program. These two trials were prompted by encouraging results from an earlier Phase 1 clinical trial in operable patients which demonstrated prolonged, disease-free survival of at least six years in three of eight patients treated at therapeutic dose levels. The new findings were presented by Daniel Laheru, M.D., assistant professor of medical oncology at Johns Hopkins Kimmel Cancer Center, and colleagues, at the annual meeting of the Lustgarten Foundation for Pancreatic Cancer Research which was sponsored by the American Association of Cancer Research and held this past weekend in San Francisco, CA.
The Phase 2 trial in patients with inoperable pancreatic cancer enrolled 50 patients, the majority of whom had failed at least two prior chemotherapy regimens. Patients were divided into two cohorts, both receiving up to six doses of GVAX® pancreatic cancer vaccine at 21-day intervals. Cohort A (30 patients) received GVAX® pancreatic cancer vaccine alone, and cohort B (20 patients) received GVAX® pancreatic cancer vaccine in combination with low-dose cyclophosphamide, a chemotherapeutic agent which has been shown in the subtherapeutic doses administered to enhance the immune response by reducing "suppressor" T lymphocyte function in the absence of a direct anticancer effect. Despite the very advanced stage and extensive prior chemotherapy in the majority of patients, there was a trend toward an improved outcome with combination therapy in cohort B by all measures of clinical activity. Forty percent of patients in cohort B demonstrated stable disease, compared with 16.7 percent in cohort A. Moreover, the median time to progression was 57 days in cohort B and 42 days in cohort A, and median survival in cohort B was 4.3 months compared with 2.3 months in cohort A. In addition, there was a correlation between survival and the patients' post-vaccination blood level of GM-CSF produced by GVAX® pancreatic vaccine. Median survival was 5.3 months for patients above the median peak level and 1.8 months for patients below that level (p=0.03). Treatment with GVAX® pancreatic cancer vaccine with or without cyclophosphamide was generally well tolerated.
In other news, the company reported the status of enrollment for the second Phase 2 trial in patients with operable pancreatic cancer who receive the vaccine after surgical resection of their tumor and adjuvant radiation chemotherapy. This study, which is being conducted at Johns Hopkins Kimmel Cancer Center, has enrolled more than 45 out of a projected 60 patients. Enrollment is expected to be completed this year and preliminary data may be available during 2005.
"The results reported from our trial in inoperable pancreatic cancer demonstrate the safety and feasibility of administering GVAX® pancreatic cancer vaccine in combination with low dose cyclophosphamide chemotherapy and suggest that this combination may have enhanced clinical activity even in patients with the most advanced stage of this highly aggressive cancer," stated Joseph J. Vallner, Ph.D., president and chief operating officer of Cell Genesys. "These findings, together with the potential survival benefit observed in the initial study in patients with operable pancreatic cancer, clearly support our continued evaluation of vaccine administration after pancreatic cancer surgery, and we are pleased with rate of patient enrollment in the parallel Phase 2 trial at Johns Hopkins."
The initial Phase 1 trial of GVAX® pancreatic cancer vaccine was conducted at Johns Hopkins Kimmel Cancer Center in 14 patients who received the vaccine following surgical resection of their tumor together with standard adjuvant radiation and chemotherapy. The results of this trial which were first reported in the Journal of Clinical Oncology in January 2001, revealed that three of eight patients who received the higher dose levels of the vaccine were alive and disease-free, and this continued to be true at their most recent follow-up of greater than six years. In addition, the three patients with prolonged disease-free survival had biopsy-proven vaccine-induced antitumor immunity, a finding which was absent in the other five patients in the same treatment groups who had progressive pancreatic cancer. The significance of these findings was underscored by the fact that all three long term survivors were judged to be at high risk for recurrent cancer due to microscopic evidence of pancreatic tumor following surgery and/or metastatic tumor in pancreatic lymph nodes. As with other GVAX® clinical trials, vaccine treatment was generally well tolerated.
The GVAX® pancreatic cancer vaccine being evaluated in this Phase 2 trial is comprised of a non patient-specific vaccine which will be developed as an "off-the-shelf" pharmaceutical product. The vaccine is administered as an intradermal (under the skin) injection. GVAX® cancer vaccines are comprised of tumor cells which have been irradiated and genetically modified to secrete granulocyte-macrophage colony stimulating factor (GM-CSF), a hormone which plays a key role in stimulating the body's immune response to vaccines. The genetically modified tumor cells are used to vaccinate patients to stimulate an immune response against their tumor. GVAX® cancer vaccines have demonstrated activity against every type of human cancer against which they have been tested to date. Cell Genesys is currently evaluating non patient-specific GVAX® cancer vaccines in prostate cancer, pancreatic cancer, leukemia and myeloma and a patient-specific vaccine in lung cancer. GVAX® vaccines have demonstrated a favorable side effect profile in over 600 patients treated in clinical trials today.
Pancreatic cancer is the fourth leading cause of cancer death in the United States. According to the American Cancer Society, in 2004, an estimated 31,860 Americans will be diagnosed with pancreatic cancer and approximately 31,270 Americans will die from the disease. Because symptoms are non-specific, cancer of the pancreas is rarely diagnosed at an early stage leaving surgical removal of the tumor as a treatment option for only approximately 20 to 30 percent of pancreatic cancer patients. The average survival time of patients with metastatic cancer of the pancreas is three to seven months.<<
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That last line is true for "inoperable" patients, who are also advanced. Virtually nothing works for these patients, and I doubt much was expected by investors from this trial, though these results show that GVAX had virtually no effect, so it certainly won't help CEGE. The parallel trial for patients at an earlier stage, might do better, but it will be measured by a longer yardstick of survival.
Cheers, Tuck |
