JPRN‐UMIN000014243.

Study name	Randomised controlled study of GnRH antagonist monotherapy and CAB with GnRH agonist plus bicalutamide for patients with metastatic prostate cancer
Methods	Study design: parallel‐group randomized open‐label controlled clinical trial Setting: multicenter, national Country: Japan
Participants	Inclusion criteria: Histopathological‐confirmed prostate cancer patients Patients with metastatic prostate cancer (Stage D) Patient's survival is expected to be more than 6 months Patients with written informed consent Exclusion criteria: Patients with history of treatment or under treatment for prostate cancer Patients with active double cancer. (Patients with history of malignant tumor within the past 5 years are regarded as having active double cancer. Basal cell carcinoma for which radical treatment was taken or superficial squamous cell carcinoma are not considered to be active double cancer.) Patients less than 20 years of age on enrollment day Any other patients who are regarded as unsuitable for this study by the investigators Target sample size: 200 Age (years): ≥ 20 years (no upper limit) Sex (M/F): male only
Interventions	Group 1: degarelix 240 mg, s.c. at Day 1; degarelix 240 mg, s.c. every 4 weeks; bicalutamide 80 mg daily (as deferred CAB therapy in the case of PSA recurrence) Group 2: leuprorelin or goserelin: s.c. injection (according to usage and administration of package insert); bicalutamide 80 mg daily
Outcomes	Primary outcomes: PSA progression‐free survival Secondary outcomes: Time to CAB treatment failure (time to treatment failure in the case of deferred CAB therapy in antagonist monotherapy group) Overall survival Progression‐free survival in image diagnosis Radiographic progression‐free survival Change of PSA Effect on hormone dynamics Change of bone metabolic markers Effect on lipid metabolism Adverse event
Starting date	July 2014
Contact information	Akira Yokomizo Kyushu University Department of Urology, Graduate School of Medical Sciences 3‐1‐1, Maidashi, Higashi‐Ku, Fukuoka, Japan, 812‐8582 Telephone: +81 (0)92‐642‐5378 Email: yokoa@uro.med.kyushu‐u.ac.jp
Notes	Funded by Astellas Pharma Inc Recruitment will be closed by July 2017. Anticipated last follow‐up date: March 2019 Corresponding author (Akira Yokomizo) quote: “No clinical data will be available until the last patient's follow up after two years.” Trial ID: JPRN‐UMIN000014243, KYUCOG‐1401