Enzalutamide plus ADT improves outcomes for metastatic hormone-sensitive prostate cancer

Results from the large international phase 3 ARCHES trial show that, in men with metastatic hormone-sensitive prostate cancer (mHSPC), enzalutamide combined with androgen deprivation therapy (ADT) significantly extended radiographic progression-free survival (rPFS) compared with ADT alone.

Enzalutamide has already demonstrated a benefit in men with metastatic and localised castration-resistant prostate cancer (CRPC), but its efficacy when combined with ADT in mHSPC patients has remained unclear. Executed worldwide at sites in the United States, Canada, Europe, South America, and the Asia-Pacific region, the ARCHES trial was a randomised, double-blind, placebo-controlled, international study that enrolled 1,150 mHSPC patients. Patients treated by ADT (with luteinising hormone-releasing hormone agonist or antagonist, or bilateral orchiectomy) were randomised to either receive a daily dose of 160 mg enzalutamide or placebo.

In the ARCHES study, the enzalutamide plus ADT arm corresponded to a 61% reduction in the risk of radiographic progression or death when compared to the placebo plus ADT arm (HR=0.39; P<0.0001).

"The significant benefit in rPFS was seen across all prespecified subgroups, including low- and high-disease volume and with or without prior docataxel therapy," explained Prof. Antonio Alcaraz (Hospital Clinic de Barcelona, Spain), who presented the study at the Breaking News session.

There was also significant improvement in other endpoints, including time to prostate-specific antigen (PSA) progression, reduction in the risk of starting a new antineoplastic therapy, and objective response rate, as compared to ADT alone.

Commenting on the study, Prof. Noel Clarke (University of Manchester, United Kingdom), put the new results into context. "Preliminary safety analysis appears consistent with the safety profile of enzalutamide in previous CRPC trails, and had acceptable toxicity in the medium term." He went on to compare ARCHES data to RCTs studying abiraterone. “This may translate to improved OS, but further follow-up is needed. CHAARTED-defined volume and LATITUDE-defined risk exclusions need to be re-visited in relation to the use of combination ATD studies in hormone-sensitive metastatic prostate cancer." [1]

1. van Soest RJ, de Wit R. BMC Med. 2015 Dec 22;13:304.

Posted on 21 May, 201917 March, 2021