Clinical Outcomes of CML Patients After Delayed Start of Nilotinib Treatment

Abstract

In developing countries, TKI is limited and many patients have delayed start of therapy. Superiority of nilotinib in delayed treatment is not well studied. We have previously recognized the possible superior effect of delayed nilotinib, and decided to analyse long-term effects. In this study we presented long-term outcomes of 70 CML patients categorized into Group 1 (n= 31, front-line nilotinib) and Group 2 (n= 39, front-line imatinib, second-line nilotinib). CCyR and MMR at 24 months on nilotinib were higher in Group 1 (88% vs. 75% and 81% vs. 59%, respectively). We further subcategorized Group 1 and 2 and also compared patients based on the length of delay between diagnosis and the start of front-line TKI treatment (Group 1A and 1B; Group 2A and 2B). Subgroup A were patients who immediately received therapy and subgroup B were patients who waited > 6 months for initial TKI. Regarding effects of delayed front-line nilotinib treatment, CCyR and MMR at 24 months did not differ significantly among in Groups 1A and 1B (83% vs. 77% and 78% vs. 69%, respectively; p= 0.924, p= 0.215, and p= 0.305). In Group 2B, the response was worse on front-line imatinib; however, clinical outcomes were improved after they received second-line nilotinib therapy. Thus, in Group 2, second-line nilotinib seemed to annul the deleterious effects of delayed start of front-line imatinib. CML patients treated with front-or second-line nilotinib had optimal responses regardless of the length of the wait period.