Data Support PCa Vaccine's Mechanism of Action
Phase 3 trial data presented at the American Association of Cancer Research annual meeting support the mechanism of action of Provenge (sipuleucel-T), a novel investigative immunotherapy for advanced prostate cancer, according to a statement issued by Dendreon Corp., of Seattle, which is developing the treatment.
Designed to stimulate a T-cell response to prostate cancer cells, Provenge targets prostatic acid phosphatase (PAP), an antigen expressed in 95% of prostate cancer.
The data were from 237 patients who participated in the immune monitoring protocol of the IMPACT (Immunotherapy for Prostate Adenocarcinoma Treatment) trial. Provenge generated antigen-specific responses, including responses to PAP; these responses were not observed in placebo recipients. Provenge also triggered both cellular and humoral immune responses in vivo that were first observed six weeks after dosing; these responses persisted at 26 weeks. In addition, Provenge induced a T-cell response, suggesting the induction of immunologic memory.
“These data strongly support our understanding of the proposed mechanism of action of active cellular immunotherapies,” said David Urdal, PhD, Senior Vice President and Chief Scientific Officer of Dendreon.