Presentation (CTI)

OBJECTIVES: Safely discontinuing tyrosine kinase inhibitor (TKI) treatment, also known as treatment-free remission (TFR), is an increasingly recognized key treatment goal in chronic myeloid leukemia (CML) therapy. For patients entering TFR, 41-51% are expected to relapse within 6 months to 1 year, while those who maintain remission beyond the first year often experience longer periods of remission than the median time suggests. Therefore, when estimating the time a patient may spend in TFR, the mean may provide a more accurate representation.
METHODS: A systematic literature review presented at ISPOR 2024 identified first-line CML clinical studies reporting TFR outcomes. Time in TFR refers to the length of time patients remained off treatment after discontinuation, without the need for treatment re-initiation. Individual patient data (IPD) from the ENESTfreedom trial, alongside reconstructed Kaplan-Meier (KM) curve data, were analysed to estimate the mean TFR duration and restricted mean TFR duration that patients spent in TFR. Restricted mean TFR duration was used to compare available data from ENESTfreedom with the selected studies at a 5 year cutoff.
RESULTS: Analysis of ENESTfreedom patient data revealed a mean TFR duration of 30 months compared to the median TFR duration of 28 months. Data from the reconstructed KM data for STIM-1 and STIM-2 studies supports this analysis with restricted mean TFR duration values of 25 months and 31 months, respectively.
CONCLUSIONS: Clinical benefits of TFR can be underestimated given the large drop off of patients within the first 6 months of TFR and reporting of median time may not reflect those who maintain remission beyond the first year. The results become more pronounced with longer study follow-up, as the majority of events occur in the first year after stopping treatment. Hence, mean TFR duration may provide a more accurate real-world evaluation, supporting improved outcome projections for eligible CML patients.