CS5001 exhibited prominent antitumor activity in both Jeko-1 and MDA-MB-231 xenograft models in a dose-dependent manner. In Jeko-1, complete regression (CR) was observed after a single administration of CS5001 at 1mg/kg (approximate 1/5th the maximum tolerated dose (MTD) in mice)...CS5001 exhibited potent and selective cytotoxicity to a variety of ROR1-expressing cell lines and showed remarkable in vivo antitumor activity. ROR1 cytometric density predicts sensitivity to CS5001 in vitro. CS5001 is a promising therapeutic candidate for ROR1-expressing hematological and solid malignancies with precision medicine potential.