Efficacy of New Therapies for Relapse after Docetaxel Treatment of Bone Metastatic Castration-resistant Prostate Cancer in Clinical Practice

Abstract

Background/Aim: To assess the efficacy of novel therapeutic agents, such as androgen receptor axis-targeted agents (ARATs) and cabazitaxel, for relapse of metastatic castration-resistant prostate cancer (mCRPC) after docetaxel in real-world practice, we performed a subanalysis using database from PROSTAT-BSI, a prospective observational study to evaluate the utility of software for quantifying bone metastases on bone scintigraphy. Patients and Methods: Patients with clinically relapsed mCRPC after docetaxel treatment who received the new agents (NEW group) and those who did not (standard of care, SOC group) were included; patients who received ARAT before DOC treatment were excluded. Overall survival (OS) after docetaxel treatment was compared between the NEW and SOC groups. Results: Patients in the NEW group had significantly better OS from the start of docetaxel than those in the SOC group (the median OS in NEW and SOC was 28.9 months vs. 14.5 months, respectively). Furthermore, regardless of the time from androgen-deprivation therapy to the start of docetaxel at mCRPC, the NEW group had a better OS from relapse after docetaxel than the SOC group. Conclusion: In clinical practice, OS of patients with relapse after docetaxel was significantly improved in the NEW group over the SOC group.