PROSPER is an international Phase III trial demonstrating the beneficial role of enzalutamide, an androgen receptor antagonist, in prolonging metastasis-free survival in men with nonmetastatic castration-resistant prostate cancer. The trial showed that the median metastasis-free survival was 21.9 months longer for those treated with enzalutamide (36.6 months) compared to those treated with placebo (14.7 months). Enzalutamide also showed prolonged time to PSA progression, PSA response, and time to initiating additional antineoplastic therapy although overall survival is not yet reached. Enzalutamide is the second antiandrogen (next to apalutamide) that has gained the United States Food and Drug Administration (US FDA) label indication for use in the setting of nonmetastatic castration-resistant prostate cancer.
Androgen Antagonists/therapeutic use* ; Antineoplastic Agents/therapeutic use* ; Benzamides ; Humans ; Male ; Nitriles ; Phenylthiohydantoin/therapeutic use* ; Prostatic Neoplasms, Castration-Resistant/drug therapy*

Despite impressive survival benefits with immunotherapy in patients with various solid tumors, the full potential of these agents in prostate cancer has yet to be realized. Sipuleucel-T demonstrated a survival benefit in this population, indicating that prostate cancer is an immunoresponsive disease; however, these results have not been matched by other agents. A large trial with ipilimumab in prostate cancer failed to meet its primary objective, and small trials with PD-1/PD-L1 inhibitors did not yield a significant improvement in overall response. However, several late-stage clinical trials are underway with other vaccines in prostate cancer. Reports of clinical benefit with immunotherapies, particularly when used in combination or a select population, have provided the framework to develop sound clinical trials. Understanding immunogenic modulation, antigen spread, biomarkers, and DNA-repair defects will also help mold future strategies. Through rational patient selection and evidence-based combination approaches, patients with prostate cancer may soon derive durable survival benefits with immunotherapies.
Animals ; Antineoplastic Agents, Immunological/therapeutic use* ; Antineoplastic Combined Chemotherapy Protocols/therapeutic use* ; B7-H1 Antigen/antagonists & inhibitors* ; Benzamides ; CTLA-4 Antigen/antagonists & inhibitors* ; Cancer Vaccines/therapeutic use* ; Humans ; Immunotherapy ; Ipilimumab/therapeutic use* ; Male ; Nitriles ; Phenylthiohydantoin/analogs & derivatives* ; Programmed Cell Death 1 Receptor/antagonists & inhibitors* ; Prostatic Neoplasms/drug therapy* ; Tissue Extracts/administration & dosage*