The lead compound, GMB‐475 (5), induced a significant and rapid degradation of BCR‐ABL in a time‐ and concentration‐dependent manner, inhibiting cellular proliferation of human CML cells with micromolar potency (50% inhibitory concentration (IC50) value of 1 μM), but not as potent as IMA (IC50 = 0.17 μM).80 This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.