ORLANDOIn patients with hormone-refractory, metastatic prostate cancer,
an allogeneic vaccine delays progression of disease and prolongs survival,
according to data presented at the 38th Annual Meeting of the American Society
of Clinical Oncology (abstract 729).
In this phase II study of 34 patients, the vaccine (GVAX, Cell Genesys,
Inc., Foster City, California) showed evidence of a dose-response relationship
in prostate-specific antigen (PSA) progression, time to progression, and
survival, setting the stage for a phase III trial scheduled to be launched in
the first half of 2003.
"The more important work is up ahead," said lead investigator Jon-athan
Simons, MD, director, Winship Cancer Institute, Atlanta. "Now that a safe
doses has been defined, larger clinical trials can be done."
The vaccine is composed of PC-3 and LNCaP tumor cells irradiated and
genetically modified to secrete granulocyte macophage colony-simulating factor
In this study, there were no dose-limiting or autoimmune toxicities in 24
patients given a lower vaccine dose (prime dose of 500 million cells, followed
by 12 booster doses of 100 million cells each) or in 10 patients given a higher
dose (same prime dose, but with booster doses of 300 million cells each).
Toxicities primarily consisted of nonserious injection site reactions, along
with fatigue, fever, and flu-like symptoms.
Trend Toward Increased Survival