CSRM617 is an ONECUT2 (OC2) inhibitor that directly targets OC2 HOX domain (KD = 7.43 µM) and disrupts OC2 target genes promoter binding. CSRM617 blocks OC2-dependent prostate cancer growth in cultures (IC50 = 4-50 µM; 48 h) via apoptosis induction (fold of untreated annexin V population = 2.3/10 µM, 3.5/20 µM; 22Rv1) and exhibits in vivo efficacy against metastases as well as the growth of established 22Rv1 tumor in mice in vivo (50 mg/kg/day ip.).