A prospective clinical phase II evaluation study on a nationwide scale, the effectiveness and safety of discontinuation of tyrosine kinase inhibitors after a previous two-step dose reduction in patients with chronic myeloid leukemia in deep molecular remission. The third periodic report on the HALF study evaluates the safety data received by the sponsor of the study during the period 6/16/2022 to 6/15/2023. Clinical evaluation is currently taking place in eight centers in the Czech Republic.