Evolution in the BCR-ABL1 transcript level on first-choice second-line 2G-TKI according to the molecular response achieved after 3 months on second-line therapy. Patients who had a BCR-ABL1/ABL1 ratio > 10% after 3 months of therapy (red circles) had a minimal reduction in the transcript level during subsequent follow-up, remaining always above the 1% mark (equivalent to a 2 log reduction commonly identified with CCyR). Patients with a transcript level at 3 months of ≤ 10% are represented by blue circles. The top row represents patients who discontinued their first-choice 2G-TKI at the various time points according to their transcript levels at 3 months.