Treatment Patterns Among Androgen Receptor Pathway Inhibitor-Experienced Patients With Metastatic Castration-Resistant Prostate Cancer: A Global Real-World Study

INTRODUCTION: Androgen receptor pathway inhibitors (ARPIs) are increasingly used earlier in the treatment sequence for prostate cancer. Contemporary real-world treatment patterns post-ARPI are unclear, especially following ARPI use in premetastatic castration-resistant prostate cancer (mCRPC) settings. This study describes contemporary treatment patterns among ARPI-experienced patients with mCRPC across the United States, France, Germany, Italy, Spain, United Kingdom, and Japan. PATIENTS AND METHODS: In this retrospective noninterventional study, recruited physicians completed electronic case reports from August-October 2023 based on medical records of adult patients who had received ≥ 1 prior ARPI and ≥ 1 systemic mCRPC therapy. Treatment patterns were summarized. First treatment for mCRPC in ARPI-experienced patients was defined as the index line. RESULTS: In total, 1014 patients (mean [SD] age at index therapy inception, 69.1 [8.5] years) were included. Initial ARPI was received in pre-mCRPC settings in 82.6% patients and as first-line mCRPC treatment in 17.4%. As index line, most patients received another (sequential) ARPI (48.4%) or docetaxel (35%). Most common sequences from preindex to index therapy were abiraterone→docetaxel (16.1%) and abiraterone→enzalutamide (10.9%). Patients with ECOG score 0-1 more commonly received taxane therapy (42%-46%) than those with ECOG score ≥ 2 (29%). CONCLUSION: Sequential ARPI use despite disease progression on a prior ARPI remains a common international practice, potentially to avoid chemotherapy-related toxicity. Sequential ARPI versus chemotherapy choice varies by patient performance status, potentially reflecting the role of patient fitness and preference in post-ARPI treatment selection. This study emphasizes the need for alternative therapies in the ARPI-refractory setting.