ABL1 and chronic myelogenous leukemia, BCR-ABL1 positive: Since the introduction of tyrosine kinase inhibitors (TKIs), care for patients with chronic myeloid leukemia (CML) has radically changed, and survival of patients with CML is now similar to survival in the general population without CML.1 However, TKIs remain very expensive, resulting in a financial burden on patients and the health care system.2 For patients with a sustained deep molecular response (MR4 or better; BCR::ABL1 ≤ 0.01% on the International Scale), attempting discontinuation of TKI therapy is safe.