Feasibility Analysis Of Prioritizing Imatinib As First-line Treatment For Chronic Myeloid Leukemia In Chronic Phase

Objective: To investigate the real-life choice of first-line treatment in the chronic phase of chronic myeloid leukemia(CML-CP),analyze the difference in overall efficacy between patients with first-line imatinib treatmet of whom patients with poor efficacy or intolerance to imatinib switching to nilotinib and patients with first-line nilotinib treatmet,and analyze feasibility of prioritizing imatinib as first-line trentment for CML-CP.Methods: We have collected clinical data of CML-CP patients who received first-line treatment with imatinib and nilotinib in China from January 2003 to July 2019.We went through retrospective analysis of the efficacy and safety of imatinib versus nilotinib for first-line for CML-CP patients,and comparative analysis of the efficacy between sustaining imatinib and switching to nilotinib for CML-CP patients with warning or failure response to first-line imatinib.We also comparatively analyzed the efficacy between first-line nilotinib patients and first-line imatinib patients managed according to the ELN recommendations.Results: A total of 332 patients were included in the study,of which 300 patients received first-line imatinib treatment and 32 patients received first-line nilotinib treatment.At 24 months of treatment,patients in first-line nilotinib group achieved a higher CCy R rate(96.9%vs.80.7%,P=0.023),MMR rate(90.6%vs.72.3%,P=0.025)and MR4.0 rate(75.0%vs.54.7%,P=0.027)than those in first-line imatinib group.At 36 months of treatment,compared with first-line imatinib,patients in first-line nilotinib group can still achieve a higher CCy R rate(96.9%vs.81.7%,P=0.029),MMR rate(90.6%vs.72.7%,P=0.027)and MR4.0 rate(81.3%vs.60.3%,P=0.020).Of the 300 patients treated with imatinib,119 patients achieved the optimal response,166 patients did not obtain the optimal response,and 15 patients were imatinib intolerance.Of the 166 patients who did not obtain the optimal response,107 patients maintained imatinib and 59 patients switched to nilotinib.The CCy R rate,MMR rate,and MR4.0 rate of patients converted to nilotinib and those who maintained imatinib at the subsequent 12 monthswere 86.4% vs.61.7%(P=0.001),69.5% vs.53.3%(P=0.042)and 45.8 vs.30.8%(P=0.055).15 patients switched to nilotinib due to imatinib-intolerant,the rate of CCy R,MMR and MR4.0 were 100%,100% and 86.6% and nilotinib tolerance was acceptable.Of the 300 patients treated with imatinib,41 patients with failure response to imatinib did not converted to second-generation TKI.The remaining 259 patients adjusted treatment according to the efficacy and adverse reactions.At 24 months of treatment,the CCy R,MMR,and MR4.0 rates of patients treated with first-line nilotinib and 259 patients managed according to the ELN recommendations were96.9%vs.86.1%(P=0.084),90.6%vs.79.2%(P=0.123),and 75.0%vs.59.8%(P=0.096),respectively.At 36 months of treatment,the CCy R,MMR,and MR4.0 rates of patients treated with first-line nilotinib and 259 patients managed according to the ELN recommendations were 96.9% vs.91.9%(P=0.314),90.6% vs.85.3%(P=0.417),81.3% vs.67.6%(P=0.114),respectively.Conclusion: The efficacy of first-line nilotinib in the treatment of CML-CP is superior to first-line imatinib.The efficacy of switching to nilotinib is superior to maintaining imatinib for patients with warning or failure response.First-line imatinib patients can achieve similar efficacy as first-line nilotinib after standardized management according to the ELN recommendations.Prioritizing imatinib as first-line treatment for chronic myelogenous leukemia is feasible and effective.