In summary, we developed a novel nanoconjugate for targeted drug delivery of Auristatin E that achieves a significant reduction of the leukemic cell burden in the bone marrow and circulating blood, and a potent blockade of leukemic cell spread to extramedullar organs in a CXCR4+ AML model. The gene discussed is CXCR4; the disease is acute myeloid leukemia.