166P Comparative assessment of prognostic outcomes between vintage hormonal therapy and androgen deprivation therapy combined with novel androgen pathway inhibitor in Japanese patients with metastatic castration-sensitive prostate cancer

Abstract

In recent years, therapeutic strategy for metastatic castration-sensitive prostate cancer (mCSPC) have been drastically changed since the introduction of combined treatment with conventional androgen-deprivation therapy (ADT) and novel androgen pathway inhibitor (ARPI). In Japanese real-world clinical practice, however, it remains common to perform vintage hormonal therapy (VHT) either by ADT alone or combined androgen blockade (CAB). The objective of this study was to analyze the impacts of upfront hormonal therapies on the prognostic outcomes in Japanese mCSPC patients. This study included 581 consecutive mCSPC patients consisting of 305 and 276 who received VHT (VHT group) and ADT plus ARPI (ARPI group), respectively, as first-line therapy. Potential parameters associated with PSA-progression free survival (PFS) and overall survival (OS) in these patients were investigated. Median PFS and OS of the 581 patients was 27 months and not reached, respectively. Multivariate analyses of several factors identified independent predictors associated with unfavorable PFS as follows: high alkaline phosphatase, high lactate dehydrogenase (LDH), number of bone metastasis ≥3, existence of symptoms, treatment with VHT, and those associated with unfavorable OS as follows: older age, poor performance status, high LDH, existence of symptoms. In LATITUDE low risk patients, the median PFSs were 36.6 months and not reached in the VHT and ARPI groups (P = 0.071), respectively, and the median OSs were not reached in both groups (P = 0.60). In LATITUDE high risk patients, the median PFSs were 12.4 months and not reached in the VHT and ARPI groups (P <0.001), respectively, and the median OSs were 40.2 months and not reached in the VHT and ARPI groups (P = 0.023), respectively. These findings suggest that it could be expected to achieve favorable prognostic outcomes in mCSPC patients, particularly those classified into LATITUDE high risk, by introducing ADT plus ARPI, rather than VHT, as first-line therapy.