Deep molecular response on imatinib treatment — results from a real-life retrospective study

Introduction: Tyrosine kinase inhibitors (TKIs) have dramatically changed the outcome of chronic myeloid leukemia (CML) patients. Recent research focused on TKI discontinuation after achieving a deep molecular response (DMR) has revealed that about half of the patients maintain the response. DMR is a key criterion for TKI discontinuation. Our retrospective, ‘real-life’ study was aimed at to estimating the proportion of patients treated with first-line imatinib (IM) who achieved DMR and thus may be candidates for discontinuation of TKI treatment in a real life setting. Material and methods: Two hundred and twenty-three patients were enrolled. All patients started IM at 400 mg daily. The median age at the time of diagnosis was 57 years (range: 17–92). Results: Eighty-five patients (43%) in the whole group achieved DMR. Early molecular response (EMR) was achieved by 136 (69%) patients and correlated with the DMR rate (53% with EMR vs 14% without, p < 0.001). Major molecular response (MMR) after a year of treatment was confirmed in 108 (55%) patients, and was predictive for achieving DMR at any time (69% with MMR vs. 24% without, p < 0.001). Conclusion: DMR can be achieved in a significant proportion of patients in a real-life setting. We observed that both the achievement of an EMR at three months and MMR at 12 months were associated with a significant advantage in terms of DMR.