A European, prospective, observational study of enzalutamide in patients with metastatic castration-resistant prostate cancer: PREMISE.

In randomized clinical trials, the androgen-receptor inhibitor enzalutamide has demonstrated efficacy and safety in metastatic castration-resistant prostate cancer (mCRPC). This study captured efficacy, safety and patient-reported outcomes (PROs) of enzalutamide in mCRPC patients in a real-world European setting. PREMISE (NCT0249574) was a European, long-term, prospective, observational study in mCRPC patients prescribed enzalutamide as part of standard clinical practice. Patients were categorized based on prior docetaxel and/or abiraterone use. The primary endpoint was time to treatment failure (TTF), defined as time from enzalutamide initiation to permanent treatment discontinuation for any reason. Secondary endpoints included prostate-specific antigen (PSA) response, time to PSA progression, time to disease progression and safety. PROs included EuroQol 5-Dimension, 5-Level questionnaire, Functional Assessment of Cancer Therapy-Prostate and Brief Pain Inventory-Short Form. Overall, 1732 men were enrolled. Median TTF with enzalutamide was 12.9 months in the chemotherapy- and abiraterone-naïve cohort (Cohort 1) and 8.4 months in the postchemotherapy and abiraterone-naïve cohort (Cohort 2). Clinical outcomes based on secondary endpoints also varied between cohorts. Cohorts 1 and 2 showed small improvements in health-related quality of life and pain status. The proportions of patients reporting treatment-emergent adverse events (TEAEs) were 51.0% and 62.2% in Cohorts 1 and 2, respectively; enzalutamide-related TEAEs were similar in both cohorts. The most frequent TEAE across cohorts was fatigue. These data from unselected mCRPC patients in European, real-world, clinical-practice settings confirmed the benefits of enzalutamide previously shown in clinical trial outcomes, with safety results consistent with enzalutamide's known safety profile.