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.

Liquid Biopsy in Progressing Prostate Cancer Patients Starting Docetaxel with or Without Enzalutamide: A Biomarker Study of the PRESIDE Phase 3b Trial.

BACKGROUND AND OBJECTIVE: The PRESIDE (NCT02288247) randomized trial demonstrated prolonged progression-free survival (PFS) with continuing enzalutamide beyond progression in metastatic castration-resistant prostate cancer (mCRPC) patients starting docetaxel. This study aims to test the associations of PFS and circulating tumor DNA (ctDNA) prior to and after one cycle (cycle 2 day 1 [C2D1]) of docetaxel and with a liquid biopsy resistance biomarker (LBRB; plasma androgen receptor [AR] gain and/or circulating tumor cells [CTCs] expressing AR splice variant 7 [CTC-AR-V7]) prior to continuation of enzalutamide/placebo. METHODS: Patients consenting to the biomarker substudy and donating blood before starting docetaxel with enzalutamide/placebo (N = 157) were included. Sequential plasma DNA samples were characterized with a prostate-cancer bespoke next-generation-sequencing capture panel (PCF_SELECT), and CTCs were assessed for AR-V7 (Epic Sciences, San Diego, CA, USA). Cox models, Kaplan-Meier, and restricted mean survival time (RMST) at 18 mo were calculated. KEY FINDINGS AND LIMITATIONS: There was a significant association of worse PFS with pre-docetaxel ctDNA detection (N = 86 (55%), 8.1 vs 10.8 mo hazard ratio [HR] = 1.78, p = 0.004) or persistence/rise of ctDNA at C2D1 (N = 35/134, 5.5 vs 10.9 mo, HR = 1.95, 95% confidence interval [CI] = 1.15-3.30, p = 0.019). LBRB-positive patients (N = 62) had no benefit from continuing enzalutamide with docetaxel (HR = 0.78, 95% CI = 0.41-1.48, p = 0.44; RMST: 7.9 vs 7.1 mo, p = 0.50). Conversely, resistance biomarker-negative patients (N = 87) had significantly prolonged PFS (HR = 0.49, 95% CI = 0.29-0.82, p = 0.006; RMST: 11.5 vs 8.9 mo, p = 0.005). Eight patients were unevaluable. An exploratory analysis identified increased copy-number gains (CDK6/CDK4) at progression on docetaxel. Limitations included relatively low detection of CTC-AR-V7. Validation of impact on overall survival is required. CONCLUSIONS AND CLINICAL IMPLICATIONS: Liquid biopsy gives an early indication of docetaxel futility, could guide patient selection for continuing enzalutamide, and identifies cell cycle gene alterations as a potential cause of docetaxel resistance in mCRPC. PATIENT SUMMARY: In the PRESIDE biomarker study, we found that detecting circulating tumor DNA in plasma after starting treatment with docetaxel (chemotherapy) for metastatic prostate cancer resistant to androgen deprivation therapy can predict early how long patients will take to respond to treatment. Patients negative for a liquid biopsy resistance biomarker (based on the status of androgen receptor (AR) gene and AR splice variant 7 in circulating tumor cells) benefit from continuing enzalutamide in combination with docetaxel, while patients positive for the resistance biomarker did not. Additionally, we identified alterations in the cell cycle genes CDK6 and CDK4 as a potential genetic cause of resistance to docetaxel, which may support testing of specific drugs targeting these alterations.

Rationale for use of an exercise end point and design for the ADVANCE (A Dose evaluation of a Vasopressin ANtagonist in CHF patients undergoing Exercise) trial.

BACKGROUND: Exercise intolerance is a primary characteristic of chronic congestive heart failure. Exercise testing is therefore widely used to evaluate the degree of functional impairment, prognosis of underlying cardiac disease, and response to treatment. Historically, studies that used exercise tolerance as an end point to evaluate the efficacy of pharmacologic interventions have been confounded by methodologic differences involving protocols, exercise end points, absence or misuse of gas exchange data, and study design. METHODS: The purpose of this study was to outline the methodology and rationale of a unique cardiopulmonary exercise trial. The design was based on prior experience from evaluation of ACE inhibitors and other interventions. The ADVANCE (A Dose evaluation of a Vasopressin ANtagonist in CHF patients undergoing Exercise) trial is a multicenter, double-blind, placebo-controlled, randomized trial investigating the effects of a vasopressin antagonist, conivaptan, on functional capacity in patients with heart failure. RESULTS: The primary end point is change in the exercise time to reach 70% of peak oxygen consumption during an incremental exercise test. Secondary end points include changes in peak oxygen consumption and other exercise parameters as well as quality-of-life indicators. The study incorporates several unique features to lessen potential methodological errors of exercise testing in heart failure, including use of a core laboratory to evaluate exercise tests, a computer program to determine the exercise end points, and validation of each site before patient enrollment. CONCLUSIONS: The results of this study will have value not only for the further use of vasopressin antagonists for heart failure therapy but also for the use of exercise testing and gas exchange determination for the evaluation of new drug therapies.