Dr. Armstrong on Updated Results 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 results from the phase 3 ARCHES trial (NCT02677896) in metastatic hormone-sensitive prostate cancer.

ARCHES is evaluating the efficacy of enzalutamide (Xtandi) plus androgen deprivation therapy (ADT) vs placebo plus ADT, as measured by radiographic progression-free survival in this patient population.

Updated data have shown that patients treated with enzalutamide and ADT lived substantially longer compared with placebo plus ADT, with a statistically and clinically significant hazard ratio of 0.66, Armstrong says. Notably, this advantage occurred despite a crossover of 30%-40% of men who were treated with placebo, and these patients were offered enzalutamide prior to disease progression, Armstrong explains.

When patients on placebo did progress, a range of commercially available drugs, including enzalutamide or abiraterone acetate (Zytiga), were used in the castrate-resistant setting, Armstrong adds. Despite the common later use of enzalutamide, early ADT plus enzalutamide provided survival benefits, pointing to the importance of treatment prior to the development of resistance, Armstrong continues.

These findings have continued to help shift treatment strategies in prostate cancer by pushing more potent therapies into earlier settings, rather than using them after disease progression, Armstrong concludes.