Efficacy of enzalutamide in subgroups of men with metastatic hormone-sensitive prostate cancer based on prior therapy, disease volume, and risk.

While enzalutamide plus androgen deprivation therapy (ADT) significantly reduces the risk of radiographic progression-free survival (rPFS) and improves overall survival in metastatic hormone-sensitive prostate cancer (mHSPC), the efficacy in clinically relevant subgroups of patients based on prior local and systemic therapy, disease volume, and risk has not been analyzed to date. These post hoc analyses of the phase 3 ARCHES trial (NCT02677896) evaluated the efficacy of enzalutamide plus ADT according to prior local and systemic treatment, disease volume, and risk, assessed at trial baseline.

In ARCHES, a global, double-blind, placebo-controlled, phase 3 study, 1150 patients with mHSPC were randomized 1:1 to receive enzalutamide (160 mg/day) plus ADT or placebo plus ADT, stratified by prior docetaxel therapy and disease volume. Primary endpoint was rPFS. Secondary endpoints included time to prostate-specific antigen progression, symptomatic skeletal events, and prostate-specific antigen and radiographic responses. Analyses of clinical endpoints were completed by prior local therapy, prior docetaxel exposure, CHAARTED (NCT00309985)-defined disease volume, and LATITUDE (NCT01715285)-defined risk groups.

Patients were randomized to enzalutamide plus ADT (n = 574) and placebo plus ADT (n = 576). Enzalutamide plus ADT significantly improved rPFS (hazard ratio: 0.39; p < 0.0001), with similar improvements reported in all subgroups based on prior local and docetaxel treatment, disease volume, and risk. Treatment benefits were observed with enzalutamide plus ADT in multiple secondary clinical endpoints in the overall population and all subgroups.

Enzalutamide plus ADT demonstrated clinical benefit across all patients with mHSPC, irrespective of prior local and systemic treatment, disease volume, and risk.

Prostate cancer and prostatic diseases. 2021 Aug 21 [Epub ahead of print]

Arun A Azad, Andrew J Armstrong, Antonio Alcaraz, Russell Z Szmulewitz, Daniel P Petrylak, Jeffrey Holzbeierlein, Arnauld Villers, Boris Alekseev, Taro Iguchi, Neal D Shore, Francisco Gomez-Veiga, Brad Rosbrook, Ho-Jin Lee, Gabriel P Haas, Arnulf Stenzl

Monash Health, Melbourne, VIC, Australia., Duke Cancer Institute Center for Prostate & Urologic Cancers, Durham, NC, USA. ., Hospital Clinic de Barcelona, Barcelona, Spain., The University of Chicago, Chicago, IL, USA., Yale Cancer Center, New Haven, CT, USA., The University of Kansas Medical Center, Kansas City, KS, USA., Lille University, Lille, France., Hertzen Moscow Cancer Research Institute, Moscow, Russia., Osaka City University Graduate School of Medicine, Osaka, Japan., Carolina Urologic Research Center, Myrtle Beach, SC, USA., University Hospital, GITUR-IBSAL, University of Salamanca, Salamanca, Spain., Pfizer Inc., San Diego, CA, USA., Astellas Pharma Inc., Northbrook, IL, USA., Eberhard Karls University of Tübingen, Tübingen, Germany.

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