Abiraterone Acetate Prolongs Survival in Metastatic Prostate Cancer

the Cancer Therapy Advisor take:

COU-AA-302 trial was conducted earlier in 2013 to evaluate whether abiraterone acetate, an androgen biosynthesis inhibitor, improved overall survival in patients with metastatic castration-resistant prostate cancer after chemotherapy.

The planned interim analysis from the trial showed that abiraterone acetate plus prednisone significantly improved radiographic progression-free survival compared with placebo plus prednisone. Recently, a placebo-controlled, double-blind, randomized study, presenting presepecified final analysis of the COU-AA-302 trial, was published.

The objective of the study was to assess the effect of abiraterone acetate plus prednisone on overall survival, time to opiate use, and use of other subsequent therapies.

There were 1,088 patients in the study who were asymptomatic or mildly symptomatic with chemotherapy-naïve prostate cancer. Patients were randomly assigned to receive either abiraterone acetate plus prednisone (abiraterone acetate group), or placebo plus prednisone (placebo group). Of the prespecified 773 death events for the final analysis, 65% of patients in the abiraterone acetate group experienced death events and 71% in the placebo group.

Results showed that the median overall survival was significantly longer in the abiraterone acetate group than in the placebo group (34.7 months [95% CI 32.7-36.8] versus 30.3 months [28.7-33.3]; hazard ratio 0·81 [95% CI 0.70-0.93]; p=0·0033).

Subsequent treatment with one or more approved agents was used in 67% of patients in the abiraterone acetate group and 80% in the placebo group. Among the patients in the placebo group, 44% subsequently received abiraterone acetate therapy.

Overall, the authors concluded that abiraterone acetate significantly prolonged overall survival compared to prednisone monotherapy in the treatment of chemotherapy-naive metastatic castration-resistant prostate cancer. The clinical and statistical significance supports a favorable safety profile for abiraterone acetate.