A prospective phase II clinical trial evaluating the efficacy and safety of tyrosine kinase inhibitor withdrawal after prior two-step dose reduction in patients with chronic myeloid leukemia in deep molecular remission The HALF clinical trial is designed as a prospective, multicenter, nonrandomized, open-label phase II study to assess the efficacy and safety of tyrosine kinase inhibitor withdrawal after a prior two-step dose reduction in patients with chronic myeloid leukemia in deep remission. The clinical evaluation of HALF could contribute to the formulation of a new disease management strategy for patients achieving sustained remission with the potential for wider benefits not only for the patients themselves, but also for the healthcare system.