Zytiga for treatment of metastatic castration-resistant prostate cancer in patients who have received prior chemotherapy containing Docetaxel
The FDA ( Food and Drug Administration ) has approved Zytiga ( Abiraterone acetate ), an oral, once-daily medication for use in combination with Prednisone for the treatment of men with metastatic castration-resistant prostate cancer who have received prior chemotherapy containing Docetaxel.
Androgens are hormones that promote the development and maintenance of male sex characteristics. However, in prostate cancer, androgens can help fuel the tumors growth. Androgen production primarily occurs in the testes and adrenal glands; in men with prostate cancer, the tumor tissue is an additional source of androgens.
Zytiga is an oral androgen biosynthesis inhibitor that works by inhibiting the CYP17 enzyme complex, which is required for the production of androgens at these three sources.
Zytiga, in combination with Prednisone, was evaluated in a phase 3, randomized, placebo-controlled, multicenter clinical study in patients who had received prior chemotherapy containing a taxane ( n=1,195 ).
Patients were randomized 2:1 to receive Abiraterone 1 gram daily in combination with Prednisone 5 mg twice daily or placebo in combination with Prednisone 5 mg twice daily ( control arm ).
Results of the pivotal phase 3 study showed that at pre-specified interim analysis, treatment with Abiraterone in combination with Prednisone resulted in a 35% reduction in the risk of death ( 14.8 months vs 10.9 months; hazard ratio, HR=0.646; p