No significant impact of response to prior androgen receptor-axis-targeted agents on the efficacy of subsequent docetaxel in patients with metastatic castration-resistant prostate cancer.

BACKGROUND: To investigate whether the response to an androgen receptor-axis-targeted (ARAT) agent is associated with the efficacy of subsequent docetaxel in metastatic castration-resistant prostate cancer (mCRPC) patients.

METHODS: This study included 114 consecutive mCRPC patients, comprising 54 and 60 patients who progressed with abiraterone acetate (AA) and enzalutamide (Enz), respectively, before the introduction of docetaxel. The impact of the response to either ARAT agent on the activity of docetaxel was assessed.

RESULTS: Following ARAT therapy, a prostate-specific antigen (PSA) response was observed in 73 of the 114 patients, of whom 33 and 40 received AA and Enz, respectively. In the 114 patients, PSA response to docetaxel was achieved in 48 (42.1%) patients, and median PSA progression-free survival (PFS) and overall survival (OS) with docetaxel were 7.2 and 17.5 months, respectively. No significant difference was noted in PSA response rate, PSA PFS or OS with docetaxel between responders and non-responders to a prior ARAT agent in the overall 114 patients, 54 receiving AA and 60 receiving Enz. Despite the absence of a significant impact of the response to a prior ARAT agent on PSA PFS or OS by univariate analysis, independent prognostic predictors were identified by multivariate analysis, as performance status (PS) for PSA PFS, and PS and visceral metastasis for OS.

CONCLUSIONS: Disease control by docetaxel may not be affected by the response to a prior ARAT agent. Therefore, a prior response to an ARAT agent should not influence the decision on the subsequent introduction of docetaxel for mCRPC patients.