Introduction: The outlook for patients with chronic myeloid leukemia (CML) has changed dramatically with the development of tyrosine kinase inhibitors (TKIs) with the current treatment goal for many patients being to obtain a durable deep molecular remission, discontinue TKI therapy, and remain treatment free.Areas covered: In this article, the authors review the data from the major TKI discontinuation studies, explore potential predictors of discontinuation outcome and look at possible mechanisms to explain the variable outcomes following TKI discontinuation including immune surveillance and leukemic stem cell (LSC) depletion following TKI treatment. Data from relevant articles published on the Pubmed database between January 2007 and January 2020 have been included.Expert opinion: The results from the majority of TKI discontinuation studies show a consistent picture with approximately half of eligible patients achieving treatment free remission (TFR). However, reliable clinical predictors or biomarkers for the outcome of TKI discontinuation remain elusive and the mechanisms to explain the diversity of discontinuation success are not completely understood. Future studies will need to focus on attempts to increase the number of patients eligible for treatment discontinuation and will likely involve drug combinations including novel agents aimed at targeting the residual LSC population and enhancement of immune surveillance mechanisms.
Keywords: Chronic myeloid leukemia; TKI discontinuation; immune surveillance; treatment-free remission.