EC approves Xtandi™ for third prostate cancer indication

The European Commission (EC) has approved Astellas Pharma’s oral once-daily therapy Xtandi™ (enzalutamide) for adult men with metastatic hormone-sensitive prostate cancer (mHSPC), a cancer with a median survival of approximately three to four years. Enzalutamide is an androgen receptor signalling inhibitor.

With the new indication, enzalutamide is now the only oral treatment approved by the EC to treat three distinct types of advanced prostate cancer: non-metastatic and metastatic castration-resistant prostate cancer (CRPC) and mHSPC.

The EC approval is based on results from the pivotal Phase III ARCHES trial which evaluated enzalutamide in men with mHSPC. The randomised, double-blind, placebo-controlled, multinational ARCHES trial (NCT02677896) enrolled 1,150 patients with mHSPC. Patients in the trial were randomised to receive enzalutamide 160mg daily or placebo and continued on androgen deprivation therapy (ADT). The primary endpoint of the trial was radiographic progression-free survival (rPFS), defined as the time from randomisation to radiographic disease progression at any time or death within 24 weeks after study drug discontinuation.

Overall, enzalutamide plus androgen deprivation therapy (ADT) significantly reduced the risk of radiographic progression or death by 61 percent versus placebo plus ADT.

“Metastatic hormone-sensitive prostate cancer patients have limited options and, unfortunately, there is a poor prognosis for many men,” said Dr Andrew Armstrong, Professor of Medicine, Surgery, Pharmacology and Cancer Biology, Director of Research in the Duke Cancer Institute’s Center for Prostate and Urologic Cancers and lead investigator of ARCHES. “The research supporting this approval provides clinical evidence showing how enzalutamide can help improve outcomes for men with mHSPC, which gives healthcare professionals in Europe the option to offer the treatment across the advanced prostate cancer disease continuum.”

The safety analyses of the ARCHES trial appear consistent with the safety profile of enzalutamide in previous clinical trials in CRPC, with Grade 3 or greater adverse events (AEs) similar for patients receiving both enzalutamide plus ADT and those who received placebo plus ADT (24.3 percent versus 25.6 percent).

The EC marketing authorization for enzalutamide in men with mHSPC is applicable to European Union (EU) member countries and Iceland, Norway and Liechtenstein.