Initial experience with abiraterone acetate in patients with castration-resistant prostate cancer

To describe the results obtained in 25 males with metastatic castration-resistant prostate cancer (MCRPC) treated with abiraterone (AA). A comparative analysis of abiraterone effectiveness and safety between our results and data published in the literature was conducted.

Bi-institutional prospective analysis of 25 consecutive patients with MCRPC undergoing treatment with abiraterone, with a mean follow-up 7.9 (3-15) months was carried out. Treatment effectiveness and safety analyses regarding baseline characteristics of patients (age, prior treatments, basal PSA, performance status, pain, metastasis) were conducted.

At 13.6 months of follow-up, the overall survival is 80% (CI 95%: 11.8-15.4). Clinical and radiological-free progression survival is 9.5 ± 1 months (CI 95%: 7.7-11.3) and biochemical response is 6.8 ± 1 months (CI 95%: 5-8.7). Only the treatment with chemotherapy impaired significantly the response time to AA [6.4 months for radiological-free progression survival (CI 95%: 4.2-8,6) and 4.3 months for biochemical-free progression survival (CI 95%: 2.6-6)]. The incidence of adverse drug events was 36%, all of them grade 1-2/4 and, in no case, suspension or reduction of the dose of AA was needed.

The treatment with AA has been effective in our series, with a tolerability considerably higher than what other studies published.