Comparasion Between Nilotinib and Dasatinib as Second-Line Therapy for Patients with Chronic Myeloid Leukemia: A Single Center Retrospective Study.

Abstract 3440

Nilotinib and dasatinib are second-generation tyrosine kinase inhibitors (TKI) used in patients with chronic myeloid leukemia (CML) resistant or intolerant to imatinib. There are no randomized clinical trials comparing these drugs in this context. The aim of this study was to compare, retrospectively, the hematological, cytogenetic and molecular response in patients submitted to these second-generation TKI at Hemorio, a public brazilian institution. A total of 114 patients were analyzed, 63 received nilotinib and 51 dasatinib as second-line therapy (55.3% and 44.7%, respectively). The following variables were equally distributed between these two groups (nilotinib vs. dasatinib, respectively): male sex (54% vs. 60.8%, p=0.46), median age at diagnosis (46 vs. 45 years, p=0.76), median time in months using imatinib before the switch (45.2 vs. 44.1, p=0.96), resistance to imatinib (98.4% vs. 98%, p=0.88), presence of the mutation T315I (3.2% vs. 3.9%, p=0.09), patients in chronic phase before the switch (85.7% vs. 86.3%, p=0.93). Use of another second generation TKI, as a third-line therapy, was necessary in 30 out of the 114 patients analyzed (26.1%) because of lack of response. This modification was slightly more frequent in the group initially submitted to nilotinib (31.7% vs. 19.6%, p=0.21). Patients who used a third-line therapy were excluded from response and survival analyzes. Response rates after the second-generation TKI were similar between these two groups (nilotinib vs. dasatinib): complete hematological response until three months (77.8% vs. 87.3%, p=0.24), complete cytogenetic response until six months (21.6% vs. 22.2%, p=0.95) and 12 months (32.4% vs. 33.3%, p=0.94) and major molecular response reached before 12 months (32.7% vs. 21.6%, p=0.25). Two-year overall survival (OS) and progression free-survival (PFS) were similar between these two groups (nilotinib vs. dasatinib, respectively): 92.2% vs. 87.8% (p=0.38) for OS and 87.8% vs. 83.7% (p=0.14) for PFS. Although not statistically significant, two-year OS was inferior in the group of patients who needed a third-line therapy (70.5% vs. 95.6%, p=0.70). Our results suggest that the response and survival rates are similar between nilotinib and dasatinib as second-line therapy for patients with imatinib resistant or intolerant CML. Also, they suggest an inferior prognosis for patients who need a third-line therapy. In this way, the choice between these two TKI for second-line therapy should be guided by the clinical characteristics and the mutation status of the patient.