In line with in vitro results, OX425 mediated considerable anticancer effects in vivo....Moreover, OX425 treatment significantly delayed acquired resistance to olaparib in BRCA1 mutated MDA-MB-436 cell-derived xenografts….Our results provide preclinical rationale for using OX425 to trigger DNA damage exhaustion and STING activation in cancer cells and initiate inflammatory responses that can be actioned by immune checkpoint inhibitors in patients bearing HRD or HRP tumors