Real-world survival outcome comparing abiraterone acetate plus prednisone and enzalutamide for nonmetastatic castration-resistant prostate cancer

Abstract

Background: There is little evidence of abiraterone acetate (AA) plus prednisone for patients with non-metastatic castration-resistant prostate cancer (nmCRPC). In this study, we conducted a comparative analysis of real-world survival outcomes between AA plus prednisone and enzalutamide (Enz) in patients with nmCRPC, utilizing our consortium dataset.

Materials and methods: The clinical records of 133 nmCRPC patients treated with first-line Enz or AA plus prednisone were analyzed. The primary endpoints of the study were overall survival (OS) and cancer-specific survival (CSS). Cumulative incidence function (CIF) using Fine and Gray models was also utilized to assess non-cancer-caused death considering the competing risk of cancer-caused death.

Results: During a median follow-up of 36 months, 34 patients (25.6%) had deceased, with a median OS of 99 months in the entire cohort. There were no significant differences in comorbidities between the Enz and AA groups. Time to PSA progression (TTPP: HR 0.81, 95% CI 0.51-1.30, P = 0.375) and CSS (HR 1.32, 95% CI 0.55-3.44, P = 0.5141) were comparable between the two groups. However, intriguingly, there was a trend towards shorter OS in patients treated with AA plus prednisone compared to Enz (HR 0.57, 95% CI 0.29-1.12, P = 0.0978, median of 99 and 69 months in Enz and AA groups, respectively). CIF analysis revealed that nmCRPC patients treated with AA plus prednisone were more likely to result in non-cancer-caused death than those treated with Enz (HR 5.22, 95% CI 1.88-14.50, P = 0.0014).

Conclusions: Our real-world survival analysis suggests that while AA plus prednisone may demonstrate comparable treatment efficacy to Enz in the context of nmCRPC, there may be an increased risk of non-cancer-caused death. Physicians should take into consideration this information when making treatment decisions for patients with nmCRPC.

Keywords: abiraterone acetate; androgen receptor signaling inhibitor; castration-resistant prostate cancer; enzalutamide; nonmetastatic castration-resistant prostate cancer.