The Role of Sipuleucel-T in Therapy for Castration-Resistant Prostate Cancer: A Critical Analysis of the Literature

ContextSipuleucel-T, an autologous antigen-presenting cell vaccine loaded with prostate acid phosphatase conjugated with granulocyte-macrophage colony-stimulating factor (GM-CSF), yielded a survival advantage in men with metastatic castration-resistant prostate cancer (mCRPC).ObjectiveCritically analyze the role of sipuleucel-T in therapy for mCRPC.Evidence acquisitionA systematic review of the literature was performed in June 2011 using Medline and an abstract search of major cancer conferences. The search strategy included the terms sipuleucel-T, APC-8015, castration-resistant, prostate cancer, and immunotherapy.Evidence synthesisThe era of targeted immunotherapy was initiated with the regulatory approval in 2010 of sipuleucel-T for asymptomatic and minimally symptomatic mCRPC. The median survival was prolonged by 4.1 mo (25.8 vs 21.7 mo; hazard ratio: 0.78; 95% confidence interval, 0.61–0.98; p = 0.03), coupled with an improvement in 3-yr survival (31.7% vs 23.0%). Outcomes were characterized by the lack of tumor regression or delay in progression. Further development is proceeding in earlier stages of prostate cancer and in the context of a host of emerging agents.ConclusionsThe addition of sipuleucel-T, an immunotherapeutic agent, to the armamentarium represents a paradigm shift in therapy for mCRPC. The rational combination and proper sequencing of sipuleucel-T with other newly approved agents (abiraterone acetate, cabazitaxel) and emerging agents (MDV3100, TAK-700, ipilimumab) will be important to evaluate.