Phase III Data Presented at AACR Show Favorable Immune Response for PROVENGE

Additional data from the phase III IMPACT (IMmunotherapy for Prostate AdenoCarcinoma Treatment) clinical trial showed evidence of immune responses in patients treated with sipuleucel-T (PROVENGE), supporting its proposed mechanism of action. The study results were presented at the American Association for Cancer Research (AACR) 101st Annual Meeting, held April 17–21, 2010 in Washington, DC.

Data from 237 patients who participated in the immune monitoring protocol in the IMPACT study demonstrated that PROVENGE generated antigen-specific responses, including responses to prostatic acid phosphatase (PAP), an antigen expressed in prostate cancer tissue, that were not seen following treatment with placebo; triggered both cellular and humoral immune responses in vivo that were first detected at 6 weeks after dosing and persisted at 26 weeks after dosing; induced a T-cell response as further evidenced by antibody isotope class switching from IgM to IgG, suggesting the induction of immunologic memory; and demonstrated a cytokine profile indicative of T-cell activation in ex vivo culture over the course of therapy, with marked increases in IL-2, IFN-gamma, TNF-alpha, and IL-17.