We found that huXBR1-402-G5-PNU is cytotoxic to proliferating ROR1+ malignant cells in vitro and suppressed leukemia proliferation and extended survival in multiple models of mice engrafted with human ROR1+ leukemia…Together, our data present compelling preclinical evidence for the efficacy of huXBR1-402-G5-PNU in treating ROR1+ hematologic malignancies.