Astellas Pharma and Pfizer announced longer-term follow-up results from an open-label extension of the Phase 3 ARCHES study, reporting a five-year follow up of overall survival (OS) benefits and a 30% reduction in the risk of death in men with metastatic hormone-sensitive prostate cancer (mHSPC) treated with XTANDI (enzalutamide), an androgen receptor pathway inhibitor (ARPI), plus androgen deprivation therapy (ADT) compared to placebo plus ADT. These data will be presented during an oral presentation at the American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago.

“Historically, the likelihood of survival at five years for men with metastatic hormone-sensitive prostate cancer was low, but with advancements in initial treatment intensification like what we’ve seen with XTANDI, this is now becoming the standard,” said Andrew J. Armstrong, MD, ScM, Director of Research at the Center for Prostate & Urologic Cancers, Duke Cancer Institute, Durham, NC, and ARCHES primary investigator.

“In our five-year follow up of the global ARCHES trial, two-thirds of men are now surviving five years, representing a 13% absolute and 30% relative improvement over standard hormonal therapy alone, with benefits in patients with high and low disease burden that are meaningful to our patients.”

“The survival benefits of intervention with XTANDI in advanced prostate cancer are well-recognized,” added Shontelle Dodson, Executive Vice President, Head of Medical Affairs, Astellas. “The collective – and growing – body of data for XTANDI continues to reinforce its long-term efficacy and patient impact in prostate cancer, including in the metastatic setting, and shows that XTANDI is changing the trajectory of those living with the disease.”

These results of the five-year follow-up from the ARCHES study will be submitted for publication in a peer-reviewed journal in the near future.

“Until recently, patients with metastatic hormone-sensitive prostate cancer faced a poor prognosis, particularly in advanced stages, often due to treatment resistance,” said Johanna Bendell, M.D., Oncology Chief Development Officer, Pfizer. “As the only androgen receptor inhibitor demonstrating sustained five-year survival in this patient population, these data further reinforce XTANDI combined with androgen deprivation therapy as the standard-of-care for treating this advanced disease.”

“Data from the eight-year follow-up of XTANDI are highly encouraging, as they show the progression-free survival and overall survival benefits are sustained out to at least eight years,” said Christopher Sweeney, MBBS, DHS, FRACP, ANZUP Cancer Trials Group Limited, Sydney, Australia, and ENZAMET follow-up primary investigator. “These results further support the value of XTANDI as a treatment regimen for metastatic hormone-sensitive prostate cancer.”