Efficacy And Safety Of Abiraterone Acetate (Aa) And Low-Dose Prednisone (P) In Japanese Patients With Newly Diagnosed, Metastatic, Hormone-Naive Prostate Cancer (Mhnpc): Subgroup Analysis Of Latitude Trial.

286Background: Patients with high-risk mHNPC have a poor prognosis. In Japan, mHNPC accounts for approximately 10% of newly diagnosed prostate cancers. AAP was approved for the treatment of castration-resistant prostate cancer in Japan in July 2014. We now report the clinical benefit of AAP with ADT in Japanese patients with newly diagnosed, high-risk mHNPC. Methods: Interim analysis of the multinational, randomized, double-blind, placebo-controlled, phase 3 study, LATITUDE, was previously reported at ASCO2017. We evaluated the superiority of AA 1g + P 5 mg + ADT (AAP group) to ADT+PBOs of AA and P (P group) in mHNPC with ≥ 2 of 3 risk factors (Gleason ≥ 8, ≥ 3 bone lesions, measurable visceral metastases) for the subgroup of Japanese patients. Results: Of 1199 total patients in LATITUDE trial, 70 patients were Japanese (AAP group, n = 35; P group, n = 35). The hazard ratio (HR) for overall survival in the AAP group versus the P group was 0.635 (95% confidence interval [CI], 0.152 to 2.659) and HR for rad...