The Oral Gonadotropin-releasing Hormone Receptor Antagonist Relugolix as Neoadjuvant/Adjuvant Androgen Deprivation Therapy to External Beam Radiotherapy in Patients with Localised Intermediate-risk Prostate Cancer: A Randomised, Open-label, Parallel-group Phase 2 Trial

External beam radiotherapy (EBRT) with neoadjuvant/adjuvant androgen deprivation therapy (ADT) is an established treatment option to prolong survival for patients with intermediate- and high-risk prostate cancer (PCa). Relugolix, an oral gonadotropin-releasing hormone (GnRH) receptor antagonist, was evaluated in this clinical setting in comparison with degarelix, an injectable GnRH antagonist. To evaluate the safety and efficacy of relugolix to achieve and maintain castration. A phase 2 open-label study was conducted in 103 intermediate-risk PCa patients undergoing primary EBRT and neoadjuvant/adjuvant ADT between June 2014 and December 2015. Patients randomly assigned (3:2) to 24-wk treatment with either daily oral relugolix or 4-wk subcutaneous depot degarelix (reference control). The primary endpoint was the rate of effective castration (testosterone