Abiraterone can prolong the survival of patients with metastatic prostate cancer

Abiraterone may prolong survival in patients with metastatic prostate cancer

Background: Extragonadal androgen biosynthesis may be associated with the progression of castration-resistant prostate cancer. We evaluated whether abiraterone acetate, an antagonist of androgen biosynthesis, could prolong overall survival in patients with metastatic castration-resistant prostate cancer receiving chemotherapy.

Methods: 1195 patients who had received docetaxel and were prepared to receive 5 mg prednisone twice daily were randomly assigned to 1000 mg abiraterone acetate group (797 patients) and placebo group (398 patients) in a 2:1 ratio. The primary endpoint was overall survival. Secondary endpoints included time to prostate-specific antigen progression (increase in PSA level according to predefined criteria), progression-free survival based on imaging observation based on predefined criteria, and PSA response rate.

Results: After a median follow-up of 12.8 months, the survival of the abiraterone acetate-prednisone group was longer than that of the placebo-prednisone group (14.8 months vs. 10.9 months, hazard ratio 0.65, 95% confidence interval 0.54-0.77, p < 0.001). The data of this study were all unblinded at the time of the interim analysis because the results exceeded the predetermined criteria for study termination.

All secondary endpoints, including time to PSA progression (10.2 months vs. 6.6 months, p < 0.001), progression-free survival (5.6 months vs. 3.6 months, p < 0.001), and PSA response rate (29% vs. 6%, p < 0.001), favored the treatment group. Mineralocorticoid-induced side effects, such as sodium and water retention, hypertension, and hypokalemia, were more likely to occur in the abiraterone acetate group than in the placebo group.

Discussion: Inhibition of androgen biosynthesis with abiraterone acetate prolongs survival in patients with metastatic castration-resistant prostate cancer who have received chemotherapy.