A prospective, multicenter study on the clinical effectiveness of abiraterone in metastatic castration-resistant prostate cancer in Korea: Pre- vs. post-chemotherapy.

Abstract

The proper treatment sequence for administering abiraterone acetate plus prednisolone (AAP) and chemotherapeutic agents has not yet been elucidated for metastatic castration-resistant prostate cancer (mCRPC). Hence, this study evaluated the effectiveness and safety of AAP in pre- and post-chemotherapy settings using real-world data. This prospective, multicenter, open-label, observational study included 506 patients with mCRPC. Patients were classified according to the timing of chemotherapy into pre- and post-chemotherapy groups. The effectiveness and safety of AAP were compared between the groups; the prostate-specific antigen (PSA) response, PSA progression-free survival, and radiologic progression-free survival were assessed; and adverse drug reactions were recorded. Among the included patients, 319 and 187 belonged to the pre- and post-chemotherapy groups, respectively. Risk classification was similar between the two groups. The PSA response was 61.8% in the pre-chemotherapy group and 39.0% in the post-chemotherapy group (p<0.001). The median time to PSA progression (5.00 vs. 2.93 mo, p=0.001) and radiologic progression-free survival (11.84 vs. 9.17 mo, p=0.002) were significantly longer in the pre-chemotherapy group. Chemotherapy status was associated with PSA (hazard ratio [HR] 1.39, 95% confidence interval [CI] 1.09-1.77) and radiologic progression (HR 1.66, 95% CI 1.18-2.33) during AAP treatment. Adverse drug reactions were reported at similar frequencies in both groups. In this postmarketing surveillance, AAP benefited patients with mCRPC, especially in settings before chemotherapy was administered, resulting in a high PSA response and longer PSA and radiologic progression-free survival with tolerable adverse drug reactions.