Flutamide as an Alternative Anti-androgen Agent and Predictor of the Efficacy of Novel Androgen Receptor-targeted Agents.

Abstract

There are few reports that verify the relationship between the therapeutic effects of flutamide and novel androgen receptor-targeted agents. We aimed to evaluate the benefits of flutamide as an alternative anti-androgen agent and its effects on the efficacy of novel androgen receptor-targeted agents. Patients with castration-resistant prostate cancer on novel androgen receptor-targeted agents without prior docetaxel therapy were included. Changes in prostate-specific antigen (PSA) level were recorded. Patients who responded well to flutamide (Flutamide effective) following initial maximum androgen blockade (MAB) showed significantly higher changes in serum PSA levels (p=0.039) and PSA-progression-free survival (PFS) rate (p=0.016) following enzalutamide therapy compared to those who did not respond well to flutamide. Multivariate analysis showed that the factor of Flutamide effective was significantly associated with a good PSA-PFS rate following enzalutamide therapy (HR=7.36, 95%CI=1.4-38.71, p=0.018). Patients showing good response to flutamide following initial MAB may achieve a satisfactory PSA-PFS rate with subsequent enzalutamide therapy.