Effectiveness and Safety of Imatinib and Nilotinib in Chronic Myeloid Leukemia: A Single-Center Study From Southern Morocco

Introduction: The prognosis of chronic myeloid leukemia (CML) has been revolutionized following the advent of tyrosine kinase inhibitors (TKIs); however, access to molecular monitoring, resistance mutation screening, and second- and third-generation TKIs remains limited in resource-constrained countries. The aim of this study was to describe the efficacy and safety profile of imatinib and nilotinib in southern Morocco. Methods: This was a single-center, retrospective study conducted in the Clinical Hematology Department of the Mohammed VI University Hospital of Agadir over a ten-year period (2014-2024), including 80 patients with CML in the chronic or accelerated phase at diagnosis. All patients received first-line imatinib, with a switch to nilotinib in cases of resistance, relapse, or intolerance. Molecular response was assessed by quantitative reverse transcription polymerase chain reaction (RT-PCR) according to the International Scale (IS), with a favorable response defined as a BCR::ABL1 transcript of ≤ 1% IS at 12 months. Survival was estimated using the Kaplan-Meier method. Results: Among the 80 patients, the mean age was 47.0 ± 17.3 years, with a slight female predominance (M/F sex ratio = 0.9). The Sokal score classified 42.5% of patients as high risk. Under imatinib, a favorable molecular response at 12 months was achieved in 50% of patients, with primary resistance in the other half. As second-line therapy, nilotinib achieved a favorable response in 32.3% of the 31 treated patients. Grade ≥ 3 toxicity was observed in 12.5% of patients on imatinib and 19.4% on nilotinib, with no grade ≥ 3 cardiovascular events. After a median follow-up of 48 months, overall survival (OS) remained at 89.9% beyond 60 months, whereas event-free survival (EFS) under imatinib was shorter (median 24 months). The Sokal score was significantly associated with EFS (p = 0.007). Conclusions: Our series is notable for the young age of patients, a female predominance, and a high proportion of high-risk Sokal scores; a profile consistent with other Moroccan cohorts. Despite a high rate of imatinib resistance, likely related to the unfavorable prognostic profile, diagnostic delay, and limitations in molecular monitoring, OS remained excellent. These findings highlight the value of expanded access to second-generation TKIs as first-line therapy and to resistance mutation screening in our setting.