Early Molecular Response to Imatinib Mesylate Predicts Long-Term Outcomes in CML Patients in A Postgraduate Research Institute — A single center Study

Abstract

Introduction: Targeted therapies are revolutionizing cancer treatment, and Imatinib mesylate stands as a prime example. This potent medication tackles specific genetic vulnerabilities in certain cancers, embodying the philosophy of precision medicine. Objectives: This study evaluated the early molecular response to Imatinib Mesylate treatment in CML patients diagnosed within the past year, specifically focusing on the achievement of MMR and CMR within the first 12 months. Methods & Materials: We conducted a longitudinal observational study from January to December 2018 in the Hematology department of BSMMU, Bangladesh. Our cohort included 28 newly diagnosed CML patients, aged 15-67 years, encompassing both genders. All participants provided written informed consent, and their clinical histories and physical examinations were meticulously documented. Following established diagnostic protocols, CML was confirmed at BSMMU's Department of Microbiology and Immunology through peripheral blood film (PBF), bone marrow morphology, and BCR-ABL detection via RT-PCR. Patients received Imatinib based on the standard treatment schedule, and their molecular response was evaluated at 6 and 12 months using BCR-ABL1 RT-PCR. Through rigorous data analysis, we aimed to gain valuable insights into the efficacy of Imatinib Mesylate in this patient population. Result: In this study, at diagnosis, the BCR-ABL1 (%) was 77.82 (±22.49) while at 06 and 12 months the mean RT- PCR BCR-ABL1 was 15.14 (±20.88) and 7.59 (±16.43) respectively. There is significant change of BCR-ABL1 at 06 and 12 months of Imatinib therapy from mean at diagnosis. Out of 28 patients, 4, 3, and 1 patients went to Log 3 (BCR-ABL1 ≤ 0.1), Log 4 (BCR-ABL1 ≤0.01%), and Log 4.5 (BCR-ABL1 ≤ 0.0032) reduction respectively. Conclusion: While our study demonstrated a significant overall drop in BCR-ABL1 levels across patients at 6 and 12 months compared to baseline (p < 0.01%), only 28.57% (8/28) achieved MMR. This suggests that achieving deeper molecular responses in CML may require individualized treatment durations or potentially exploring combination therapies for some patients. Further research with larger cohorts is needed to optimize therapeutic strategies for improved MMR rates in CML.