Outcomes of chronic myeloid leukemia without major molecular response after two years of tyrosine kinase inhibition

Among patients with chronic myeloid leukemia (CML) is achieving major molecular response (MMR) with BCR::ABL1 tyrosine kinase inhibitors (TKIs) associated with lower risk of progression to advanced phase disease and higher chances of treatment-free remission. A study at MD Anderson Cancer Center (Houston, TX) investigated long-term outcomes of CML patients without MMR after two years of TKI treatment. Among these patients, achieving major cytogenetic response (MCyR), roughly equivalent to BCR::ABL1 transcript levels < 10%, was associated with good long-term overall survival (88% after ten years) and CML-specific survival (95% after ten years). Achievement of MCyR within the first two years of treatment predicted for better OS (HR 0.43; p=0.03). Among patients aged 60 years or older at diagnosis mortality was primarely due to comorbidities unrelated to CML, with ten-year OS of 55% and ten-year CML-specific survival of 100%. The authors conclude that achievement of MCyR within two years is a reasonable milestone in CML.