A phase II study is currently investigating whether CML-CP patients with a sustained complete molecular response (12 months; ≤0.0032 % or 4.5-log reduction of BCR–ABL transcript from standardized baseline) on dasatinib maintain undetectable or minimally detectable BCR–ABL residual disease upon treatment discontinuation (BMS 2013a). This evidence concerns the gene ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive.