Differentiating factors in treatment-free remission trials: impact of study design on results and clinical applications.

For patients with chronic myeloid leukemia in chronic phase with sustained deep molecular responses on long-term tyrosine kinase inhibitor (TKI) therapy, treatment-free remission (TFR) feasibility has been established. TFR is now a treatment goal for patients meeting specific criteria; NCCN Clinical Practice Guidelines in Oncology (NCCN Guidelines® ) for CML have developed criteria for attempting TFR outside clinical trials, and TFR was added to the US Food and Drug Administration-approved nilotinib label. Importantly, TFR studies vary in design and characteristics of participating patients. We discuss key study design elements to consider when assessing results from TFR trials, including criteria for attempting TFR, characteristics of enrolled patients, use of a consolidation phase (whereby patients continue TKI treatment on study before attempting TFR), and criteria for restarting TKI therapy. Finally, we review the criteria outlined in the NCCN Guidelines® for TFR outside clinical trials and compare to criteria used in TFR studies.