Company completes target enrollment in PCa immunotherapy study

Dendreon Corp. has completed enrollment of more than 500 U.S. and Canadian patients in the phase III IMPACT (IMmunotherapy for Prostate AdenoCarcinoma Treatment) clinical trial of sipuleucel-T (Provenge) for the treatment of advanced prostate cancer. The IMPACT study is a double-blind, randomized, placebo-controlled trial designed to measure overall survival in men with metastatic hormone-refractory prostate cancer receiving sipuleucel-T versus placebo.

Earlier this year, Dendreon received a complete response letter from the FDA that asked for additional evidence that would support the efficacy of sipuleucel-T. Subsequently, Dendreon received confirmation that the FDA will accept either a positive interim or positive final analysis of overall survival from the IMPACT study to amend the biologics license application and support the efficacy claim for sipuleucel-T.

The primary endpoint of the study is overall survival, and the secondary endpoint is time to objective disease progression. Patients with metastatic androgen-independent prostate cancer were eligible. The company currently expects an interim analysis for overall survival to be performed in the second half of 2008.

Enrolling 500-plus patients into the study is a “major achievement,” as the data from this trial may provide the FDA with the additional clinical data needed for the approval of sipuleucel-T, according to a Dendreon statement.