A 65-year-old man presents to his primary care physician for a regularly scheduled check-up. Routine blood work demonstrates a white blood cell (WBC) count of 34,000/µL. He is referred to hematology for follow-up regarding his complete blood count (CBC), which is concerning for chronic myeloid leukemia (CML). He is found to have t(9;22) on FISH (fluorescence in situ hybridization) and, following a discussion between the patient and physician, he is started on imatinib 400 mg daily. During the first month, the patient tolerates this therapy well and has no cytopenias or abnormalities on liver function testing.