Treatment-Free Remission: a New Therapeutic Goal in Chronic Myelogenous Leukemia

Chronic myelogenous leukemia (CML) is a chronic myeloproliferative neoplasm characterized by the presence of Philadelphia chromosome [t(9:22)] leading to the presence of pathognomonic fusion gene product, BCR-ABL1. This leads to constitutive activation of ABL1 kinase. CML was a difficult-to-treat illness until the advent of small molecule tyrosine kinase inhibitor (TKI), imatinib which revolutionized therapy of CML. Since then, multiple second- and third-generation TKIs have been formulated which have proven effective and has led to marked improvement in survival. In this article, we review currently available data on possibility of holding TKI therapy in patients in deep remission [treatment-free remission (TFR)] and safety of this approach.

As CML treatment has become more effective, new questions have emerged, most important being whether the treatment with TKIs can ever be stopped. This is especially relevant in patient experiencing side effects from therapy or who may be subject to increased health risks due to treatment. There is now evidence that some CML patients who have achieved stable deep molecular response can safely stop TKI. Furthermore, patients can safely re-establish remission after restarting their TKI therapy in the situation of relapse. CML is highly treatable disease, but the treatment has untoward physical and socioeconomic consequences. The idea of TFR is hence attractive. There is a growing body of evidence that some CML patients who have achieved stable deep molecular response can safely stop TKI.