Background: Patients with castration-resistant prostate cancer (CRPC) had extended responses to the androgen receptor antagonist ODM-201, in phase 1/2 studies.
Objective: To evaluate the safety and antitumour activity of prolonged ODM-201 treatment in patients with CRPC.
Design, setting, and participants: The ARADES trial was a multicentre phase 1 (dose escalation) and phase 2 (dose expansion) trial; 134 patients with CRPC were stratified by previous chemotherapy to receive ODM-201. This paper reports extended follow-up in CYP17 inhibitor (CYP17i)-naïve patients.
Intervention: Patients (n=77) received oral ODM-201 twice daily at daily doses of 200-1800mg.
Outcome measurements and statistical analysis: Safety, measured as the occurrence of adverse events (AEs), prostate-specific antigen (PSA), and radiographic progression.
Results and limitations: The safety profile of extended ODM-201 treatment (median treatment duration 8.2 mo, 95% confidence interval [CI] 5.6-11.0) was consistent with that reported at the time of the original data cutoff in the main ARADES trial, with no unexpected safety concerns over time. The majority of AEs (61.1%) were mild (grade 1); the most common AE was fatigue/asthenia (35.1% of patients), with no clear relationship to ODM-201. Median time to PSA progression was 25.2 mo (95% CI 11.3-25.2) for chemotherapy-naïve men and not reached (NR; 95% CI 5.5-NR) for chemotherapy-pretreated patients; a trend for improved antitumour response was observed for chemotherapy-naïve patients. The median time to radiographic progression was longer for chemotherapy-naïve (14.0 mo, 95% CI 8.1-33.3) than for chemotherapy-pretreated (7.2 mo, 95% CI 2.7-11.0) patients.
Conclusions: Prolonged exposure to ODM-201 was well tolerated, with no additional safety concerns; disease suppression was sustained, especially in chemotherapy-naïve patients. These data support further development of ODM-201 in men with CYP17i-naïve CRPC.
Patient summary: Extended ODM-201 therapy was well tolerated, with beneficial antitumour activity in men with advanced prostate cancer, indicating that ODM-201 may represent a new active treatment for men with CRPC. This extension trial is registered at ClinicalTrials.gov (www.clinicaltrials.gov) under identification number NCT01429064.
Keywords: Androgen receptor; Androgen receptor antagonist; Antiandrogen; ODM-201; Prostate cancer.
Copyright © 2017 European Association of Urology. Published by Elsevier B.V. All rights reserved.