Background: The addition of either docetaxel or abiraterone acetate plus prednisone to androgen deprivation therapy (ADT) improves overall survival (OS) compared with ADT alone in men with mHSPC. It is hypothesized that other androgen receptor (AR)-targeted therapies could be combined with docetaxel for mHSPC. Darolutamide (ODM-201) is an investigational oral AR antagonist with a unique chemical structure and negligible blood-brain barrier penetration that inhibits tumor growth by binding to AR and AR mutants (eg, W742L and F877L) with high affinity and specificity. In phase 1/2 ARADES and phase 1 ARAFOR trials, darolutamide demonstrated antitumor activity and was well tolerated in men with metastatic castration-resistant prostate cancer (mCRPC). ARASENS will evaluate the addition of darolutamide to standard ADT and docetaxel in men with mHSPC. Methods: This international, randomized, double-blind, placebo-controlled phase 3 trial (NCT02799602) is being conducted at > 300 sites in 23 countries. ~1300 men with newly diagnosed mHSPC will be randomized 1:1 to darolutamide (600 mg orally twice daily) or matching placebo. All patients will receive standard ADT + docetaxel (6 cycles). Patients will be stratified by disease extent and alkaline phosphatase level. Key inclusion criteria: histologically or cytologically confirmed PC with documented metastases, started ADT ± first-generation antiandrogen therapy ≤12 weeks before randomization, and ECOG performance status 0-1. The primary end point is OS. Secondary end points include time to mCRPC, initiation of subsequent anticancer therapy, symptomatic skeletal event (SSE)-free survival, time to first SSE, first opioid use, pain progression, and worsening of physical symptoms. Safety will be assessed. ARASENS is actively enrolling at > 280 sites across 23 countries. Clinical trial information: NCT02799602