Proper use of novel agents for castration-resistant prostate cancer

Docetaxel is the only chemotherapy agent for castration-resistant prostate cancer (CRPC) that has been proven to prolong overall survival. In 2014, novel agents for CRPC including the CYP17 inhibitor, abiraterone, the antiandrogen agent, enzalutamide, and the taxane anticancer agent, cabazitaxel were also approved for use in Japan. These novel agents brought great advantages to both patients and physicians, but led to serious concerns as to how exactly these drugs should be used. There is no definitive answer as to how to use these agents with regard to proper sequence, proper patient selection, proper drug combination and proper administration timing. Accordingly, we utilize these agents sequentially based on a consensus set forward in guidelines, whilst considering some clinicopatholo- gical factors as well as the patient's condition and preferences. Several clinical trials have been on-going in an effort to obtain some answers to these problems, and these trials may reveal how to properly select a CRPC agent in the future. In addition, research into biomarkers for proper patient selection is being actively conducted, which may make it possible to select the mostbeneficial therapeutics based on information obtained from such biomarkers. In this review, we present the current status and future perspective on the proper use of therapeutic agents for CRPC.