Ravi Salgia, MD, PhD, and colleagues at Dana-Farber
Cancer Center presented an encouraging follow-up
report on an initial clinical trial of Cell Genesys’ GVAX lung cancer vaccine
at the Ninth World Conference on Lung Cancer in Tokyo, Japan. The trial was
conducted in patients with advanced non-small-cell lung cancer, the majority
of whom had failed prior treatment with surgery, radiation, and/or chemotherapy.
Of 25 patients who received the complete course of vaccinations,
18 demonstrated enhanced antitumor immunity as measured by delayed-type
hypersensitivity skin reactions. In addition, 2 patients continued to experience
disease-free survival for more than 2 years after treatment and 3 other patients
were reported to have stable disease without evidence of tumor progression after
15, 8, and 4 months, respectively. Treatment with the GVAX vaccine was safe and
well tolerated in the outpatient setting, the investigators noted.
This initial clinical trial of the GVAX vaccine in lung cancer
is evaluating a patient-specific product format in which the vaccine is prepared
from the patient’s own tumor cells. The feasibility of this approach was
demonstrated by the successful preparation of the vaccine for over 90% of
patients enrolled in the study.
Phase I/II Trial Initiated
Based on the results of the initial trial, Cell Genesys
initiated a multicenter phase I/II trial of the GVAX lung cancer vaccine in
patients with both early-stage and advanced non-small-cell lung cancer. More
than 35 patients have been enrolled in this trial to date. In addition, Cell
Genesys plans to develop a non-patient-specific GVAX product for lung cancer,
because other non-patient-specific GVAX vaccines have previously been reported
to demonstrate encouraging results in initial clinical trials in prostate cancer
and pancreatic cancer.
"We are encouraged by the longer-term follow-up report on
this initial GVAX lung cancer vaccine trial, particularly since lung cancer has
been largely unresponsive to other immunotherapies to date," said Joseph J.
Vallner, PhD, executive vice-president and chief operating officer at Cell
Genesys. "GVAX cancer vaccines have now demonstrated antitumor activity in
all five cancers tested to date, including prostate cancer, lung cancer,
pancreatic cancer, kidney cancer, and melanoma."
Tumor Cell Modified and Irradiated
GVAX cancer vaccines are comprised of tumor cells that have been
genetically modified to secrete granulocyte-macrophage colony-stimulating
factor. The genetically modified tumor cells are then irradiated for safety and
used to vaccinate patients to stimulate an immune response against their tumor.
The company’s lead GVAX cancer vaccine program targets patients with recurrent
prostate cancer and is currently being evaluated in two multicenter phase II
trials. Additionally, a phase II trial of the GVAX pancreatic cancer vaccine and
phase I trials of the GVAX vaccine for myeloma and leukemia are expected to
begin by early 2001.
At the American Society of Clinical Oncology meeting in May
2000, Cell Genesys announced encouraging data from a phase I trial of a GVAX
pancreatic cancer vaccine and a preclinical trial of a GVAX vaccine for
leukemia. In a human clinical trial in 14 pancreatic cancer patients conducted
at the Johns Hopkins Oncology Center, 3 of 8 patients who received the two
highest doses of the vaccine are alive and free of disease more than 2 years
later, whereas all 6 patients receiving the two lowest doses have relapsed.
These patients received the vaccine following surgery and adjuvant radiation and