Treatment patterns and deep molecular response in chronic phase - chronic myeloid leukemia patients treated with second-line nilotinib or dasatinib: a multi-country retrospective chart review study

Achievement of MR4.5 (BCR-ABL1 <= 0.0032% on international scale) is an important goal of tyrosine kinase inhibitor (TKI) treatment for patients with chronic myeloid leukemia (CML). This study describes treatment patterns by region and assesses time to achieve MR4.5 in patients with CML - chronic phase (CP) treated with second-line nilotinib or dasatinib in 10 countries. A multivariate Cox proportional hazards model was used to assess time to MR4.5 for nilotinib versus dasatinib. The model accounted for the competing-risk event of TKI resistance, included random effects for country clustering, and was adjusted for baseline covariates. The study included 280 patients treated with either nilotinib (N = 135 [48%]) or dasatinib (N = 145 [52%]) as second-line TKI with median treatment durations of 19.1 and 18.7 months, respectively. Nilotinib was observed to be better in achieving MR4.5 than dasatinib (adjusted hazard ratio = 1.37, 95% CI [1.11, 1.69]) suggesting second-line nilotinib may perform better in achieving MR4.5 than dasatinib.