The efficacy and safety of androgen receptor signaling inhibitors in patients with non-metastatic castration resistant prostate cancer

Abstract BACKGROUND The treatment paradigm for non-metastatic castration resistant prostate cancer (nmCRPC) has changed in recent years. An observational multicenter study was conducted to evaluate the effectiveness of androgen receptor signaling inhibitors (ARSI) as a first-line treatment for patients with nmCRPC. METHODS The primary endpoint of this study was to evaluate the efficacy and safety of ARSI in native Japanese patients who received ARSI as a first-line treatment for nmCRPC. The secondary endpoint was to develop a novel system to stratify the prognoses of these patients. RESULTS In total, 160 patients were enrolled in this study. Within a median follow-up period of 23 months, the median overall survival (OS) was not reached, whereas the median progression-free survival was 26 months. Multivariate Cox regression analyses showed that the time to CRPC, PSA level at the initiation of nmCRPC treatment, and Geriatric Nutritional Risk Index (GNRI) were independent predictors of OS. The patients were subsequently divided into three groups as follows: Group 1, 57 patients with negative or one positive independent OS predictor; Group 2, 38 patients with two positive independent OS predictors; and Group 3, 10 patients with three independent OS predictors. The OS differed significantly among the three groups (p < 0.0001). CONCLUSION ARSI may provide favorable outcomes for Japanese patients with nmCRPC as a first-line treatment. Time to CRPC, PSA level at the initiation of nmCRPC treatment, and GNRI are potential predictors of OS in Japanese patients with nmCRPC who received ARSI as a first-line treatment.