Andrew Armstrong, MD, MSc, Discusses Key Findings From ARCHES in mHSPC at 2021 ESMO

CancerNetwork® sat down with Andrew Armstrong, MD, MSc, at the 2021 European Society for Medical Oncology Congress to talk about overall survival results found the phase 3 ARCHES study.

At the 2021 European Society of Medical Oncology, CancerNetwork® spoke with Andrew Armstrong, MD, MSc, of Duke University Medical Center, about positive overall survival results from the ARCHES trial (NCT02677896).1 He also discusses how the use of enzalutamide (Xtandi) in this trial paved the way for approval by the FDA as treatment of men with metastatic hormone-sensitive prostate cancer.2 


As presented at ESMO 2 weeks ago, we updated the overall survival results, which is a key secondary endpoint. About 3 years ago, we had presented the radiographic progression-free survival results, which was the primary end point; this was a very positive study.3 In fact, the data on radiographic progression-free survival was so substantial that the FDA approved enzalutamide in this setting for men with metastatic hormone-sensitive disease, as well as the European Union. Enzalutamide is a standard of care option that is now used. However, at the time in 2018 when we presented and published our results, we did not have mature survival data.

Having data on survival really will add to the clinical benefits that are in treatment decision making these men are faced [with] in this setting. With additional follow-up, 342 patients now have passed away with longer-term follow-up at about 44 months. We see that enzalutamide improved overall survival with a hazard ratio 0.66, which was highly clinically meaningful, and [with] a P value that was less than .0001. That means a 34% delay in the risk of death over time as compared with standard of care alone. This is a great result for our patients. We’re seeing these results despite about 40% of patients [in the placebo group] crossing over as part of the study. We crossed over patients [because] ethically that was the right thing to do for this study; [we needed to] to offer patients who were receiving the placebo access to enzalutamide so they could have benefits from the study too. We’re seeing survival benefits despite many men receiving enzalutamide, and many other life prolonging hormonal and chemotherapies after the study.


1. Armstrong AJ, Iguchi T, Azad AA, et al. Final overall survival (OS) analysis from ARCHES: A phase III, randomized, double-blind, placebo (PBO)- controlled study of enzalutamide (ENZA) + androgen deprivation therapy (ADT) in men with metastatic hormone-sensitive prostate cancer (mHSPC). Annal Oncol. 2021;32(5):S1283-S1346. doi: 10.1016/annonc/annonc741

2. FDA approves enzalutamide for metastatic castration-sensitive prostate cancer. News Release. FDA. December 16, 2019. Accessed October 6, 2021.

3. Armstrong AJ, Szmulewitz RZ, Petrylak DP, et al. ARCHES: A randomized, phase III study of androgen deprivation therapy with enzalutamide or placebo in men with metastatic hormone-sensitive prostate cancer. J Clin Oncol. 2019;37(32):2974-2986. doi:10.1200/JCO.19.00799