Rationale and motivating factors for treatment-free remission in chronic myeloid leukemia

With BCR-ABL1 tyrosine kinase inhibitors (TKIs), such as imatinib, nilotinib, dasatinib, bosutinib, and ponatinib, many patients with chronic myeloid leukemia in chronic phase (CML-CP) can expect to live near-normal life spans. Current treatment recommendations of the National Comprehensive Cancer Network and the European LeukemiaNet state that patients with CML-CP should remain on TKI therapy indefinitely. However, there is increasing evidence from clinical trials that some patients with sustained deep molecular responses may be able to achieve treatment-free remission (TFR), whereby they can suspend TKI therapy without losing previously achieved responses. With many patients achieving deep molecular responses to TKI therapy, there is growing interest in whether such patients can achieve TFR. In addition, adverse events (AEs) with long-term TKI therapy, including both the potential for later-emerging AEs and chronic, low-grade AEs, represent a major motivator for oncologists and their patients to investigate the feasibility of TFR. In this review, we provide an overview of data from TFR clinical trials, discuss the importance of achieving a deep molecular response to TKI treatment, and consider potential reasons for investigating TFR following TKI therapy.