Dr. Armstrong on Findings From a Post-Hoc Analysis of the ARCHES Trial in mHSPC

Andrew J. Armstrong, MD, MSc, professor of medicine, professor in surgery, professor in pharmacology and cancer biology, Duke University School of Medicine, member, Duke Cancer Institute, discusses updated findings from a post-hoc analysis of the phase 3 ARCHES trial (NCT02677896) in metastatic hormone-sensitive prostate cancer (mHSPC).

The ARCHES trial evaluated enzalutamide (Xtandi) plus androgen deprivation therapy (ADT) vs placebo plus ADT, and the results demonstrated improved radiographic progression-free survival (PFS) and overall survival (OS) with enzalutamide. The post-hoc analysis evaluated the long-term survival benefit with enzalutamide vs placebo across patients classified with high and low disease volume in addition to localized disease (M0) and de novo disease (M1) at diagnosis.

A survival benefit was noted across all patient subsets, Armstrong says. Differences in sample sizes of subgroups added to the confidence of the results, Armstrong explains. Point estimates across subgroups were similar, suggesting that enzalutamide can prolong life in all patients, regardless of how metastatic disease is reached or the amount of metastatic disease measured, Armstrong says.

About one-third of patients on the ARCHES trial crossed over from placebo to enzalutamide, and adjusted analyses for that crossover effect generated consistent signals in all subgroups, Armstrong concludes.