Xtandi^® reduces prostate cancer death risk by 34 percent

Astellas and Pfizer have announced that Xtandi^® (enzalutamide) improved overall survival (OS) in the ARCHES study in men with metastatic hormone-sensitive prostate cancer (mHSPC, also known as metastatic castration-sensitive prostate cancer). The Phase III, randomised, double-blind, placebo-controlled trial compared Xtandi plus androgen deprivation therapy (ADT) to placebo plus ADT in men with mHSPC and overall survival (OS) was a key secondary endpoint.

Xtandi plus ADT reduced the risk of death by 34 percent compared to placebo plus ADT. Median OS was not reached in either treatment group. The safety profile in both study arms was consistent with findings from the primary analysis.

The primary results from the ARCHES trial were published in the Journal of Clinical Oncology in 2019. The study met its primary endpoint of radiographic progression-free survival (rPFS) as assessed by independent central review, finding that prostate cancer treatment with Xtandi plus ADT demonstrated a 61 percent reduction in the risk of radiographic disease progression or death compared with ADT alone in men with mHSPC. The median follow-up time was 14.4 months. Median rPFS was not reached with Xtandi plus ADT versus 19.0 months with placebo plus ADT. At the time of the primary analysis, OS data were not mature.

In the ARCHES primary analysis, Grade 3 or greater adverse events (AEs) were similar for patients receiving both Xtandi plus ADT and those who received placebo plus ADT (24.3 percent versus 25.6 percent). Common AEs that were reported more often in patients treated with Xtandi plus ADT versus those treated with ADT alone included hot flush, fatigue, arthralgia, hypertension, nausea, musculoskeletal pain, diarrhoea, asthenia and dizziness.

“Overall survival benefit has been observed in patients treated with enzalutamide in three stages of advanced prostate cancer – metastatic castration-resistant prostate cancer, non-metastatic castration-resistant prostate cancer, and now in metastatic hormone-sensitive prostate cancer,” said Dr Andrew Armstrong Director of Research in the Duke Cancer Institute’s Center for Prostate and Urologic Cancers. “The results from ARCHES provide valuable data on the clinical profile of enzalutamide in this earlier disease setting.”