Chronic Myeloid Leukemia (CML) is a chronic leukemia, often identified in asymptomatic people with a median age of diagnosis in Canada of 64 years. It accounts for 15% of all leukemias. Previous to the introduction of oral tyrosine kinase inhibitors (TKI’s) such as imatinib (Gleevec®) in 2001, 8-year survival was 15% following diagnosis. The use of TKI’s has led to an 8-year overall survival rate reaching 87%, thus nearly matching age matched controls. With this, the prevalence of CML has continued to rise with a predicted 112,000 in the USA this year.

Current guidelines recommend lifelong TKI treatment to maintain a deep and sustained molecular response (DMR). Despite the excellent success of TKI treatment, a therapeutic option for CML is the concept of stopping TKI treatment in patients to enter treatment-free-remission (TFR). The results from several clinical trials suggest that approximately half of the patients can remain in remission after stopping their TKI treatment once they achieve a deep molecular response and meet specific laboratory parameters. This is of immense clinical significance because there are many issues that come with life-long use of TKI therapy.

Our goal is to test a new paradigm for stopping TKIs in CML patients. This paradigm is one that will be more universally accessible for patients across Canada. This pilot trial will be the basis of a larger trial in Ontario.