Upfront Androgen Receptor-Axis-Targeted Therapies in Men with De Novo High-Volume Metastatic Hormone-Sensitive Prostate Cancer.

Purpose: The extent of effectiveness of upfront androgen receptor-axis-targeted therapies (ARAT) versus total an- drogen blockade (TAB) in improving prostate cancer-specific survival (CSS) and progression-free survival (PFS) in a real-world sample of Japanese patients with high-volume mHSPC remains unclear. We, therefore, investigated the efficacy and safety of upfront ARAT versus bicalutamide for de novo high-volume mHSPC in Japanese pa- tients. Material and Methods: This was a multicenter retrospective study that analyzed CSS, clinical PFS, and adverse events (AEs) in 170 patients with newly diagnosed high-volume mHSPC. Fifty-six patients were treated with up- front ARAT, and 114 of them were prescribed bicalutamide in addition to ADT between January 2018 and March 2021. The primary and secondary endpoints were CSS and PFS, respectively. A 1:1 nearest neighbor propensity score matching (PSM) with a caliper of 0.2 was performed to match the ARAT group to TAB patients. Results: During the follow-up for a median of 21.5 months, the median CSS was not reached and 37 months in the upfront ARAT and total androgen blockade (TAB) groups, respectively (log-rank test: P = 0.006) by propensity score matching (PSM). Moreover, while the PFS of ARAT was unreached, the median PFS of TAB was 9 months (log-rank test: P < 0.001). Nine patients discontinued ARAT owing to grade ≥ 3 AEs; one patient who was treated with TAB had a grade 3 AE. Conclusion: Upfront ARAT significantly prolonged the CSS and PFS of patients with high-volume mHSPC better than TAB, although ARAT was associated with a higher rate of grade ≥ 3 AEs. Upfront ARAT can be more ben- eficial for patients with de novo high-volume mHSPC than TAB. [ABSTRACT FROM AUTHOR]