Sipuleucel-T (Provenge) can generate a circulating immune response to treat men with metastatic castrate-resistant prostate cancer, as per its FDA-approved indication.1 A neoadjuvant trial was performed to investigate whether earlier use of sipuleucel-T can generate an immune response in the prostate gland. This study suggests that sipuleucel-T treatment increases the number of immune cells in the prostate tumors, noted lead author Lawrence Fong, MD, UCSF Comprehensive Cancer Center, San Francisco.
Dr. Fong presented the results at the recent 2012 Genitourinary Cancers Symposium in San Francisco. Several clinical trials are ongoing to evaluate the effect of the vaccine in earlier stages of disease, he noted.
Phase II Study Details
The phase II trial included 42 patients with localized prostate cancer slated for radical prostatectomy. Patients received three planned infusions of sipuleucel-T at 2-week intervals prior to radical prostatectomy. Prostate specimens were obtained pretreatment and following sipuleucel-T treatment. Radical prostatectomy subjects were further randomly assigned to receive a booster treatment with the vaccine or no further treatment and were followed for 72 weeks.
Treatment with the vaccine was safe, and use of the vaccine did not appear to affect surgery and postoperative course. Neoadjuvant sipuleucel-T increased the numbers of CD3+, CD3+/CD4+, and CD3+/CD8+ cells in prostate cancer tissue at the interface of the benign and malignant glands, suggesting that treatment promotes the infiltration of T cells at the prostate tumor site. ■
Disclosure: Dr. Fong reported receiving research report from Dendreon.
1. Fong L, Weinberg VK, Corman JM, et al: Immune responses in prostate tumor tissue following neoadjuvant sipuleucel-T in patients with localized prostate cancer. 2012 Genitourinary Cancers Symposium. Abstract 181. Presented February 3, 2012.