Therapeutic options for metastatic castration resistant prostate cancer : has the situation improved?

Limited treatment options for Castration Resistant Prostate Cancer (CRPC) still remain a major challenge. Despite therapeutic advances, most patients with malignant PCa have a poor prognosis. Since the year 2000, we have rapidly expanded our understanding of the molecular mechanisms underlying CRPC and this has led to an unprecedented number of new drug approvals within a short span of time. Recently, four new agents namely Abiraterone Acetate, Enzalutamide, Cabazitaxel, and Radium-223 have been shown to be effective in the post-chemotherapy setting in CRPC. The continued dependency of CRPC on androgen synthesis has seen the development of a number of new anti-androgen therapies, with abiraterone acetate and Enzalutamide being the most promising discoveries. Immunotherapeutic approaches have also found their niche in PCa with Sipuleucel-T shown to be effective in minimally asymptomatic CRPC. Research focussed on bone-targeting therapies has witnessed the arrival of promising new drugs with Denosumab and Radium-223 displaying improved survival of patients with CRPC. This review briefly discusses the findings and limitations from ongoing and completed clinical trials of novel treatments and regimens. In addition, potential mechanisms of therapy resistance and future challenges are discussed.