The results showed that p-niclosamide prohibited the in vivo leukemic burden of BaF3-BCR-ABL-T315I cells and prolonged the survival of the mice-bearing BaF3-BCR-ABL-T315I cells, which further verified the in vivo anti-leukemic effectiveness of p-niclosamide in CML. This evidence concerns the gene BCR and chronic myelogenous leukemia, BCR-ABL1 positive.