Real-World Evidence of Treatment-Free Remission in Chronic Myeloid Leukemia at an Academic Center in the Deep South
Authors: Bascug Greg , Bourne Garrett , Diebold Kendall , Knapp Joshua , Bachiashvili Kimo , Rangaraju Sravanti , Vachhani Pankit , Bhatia Ravi , Jamy Omer 
Published: December 2023

Background: Treatment-free remission (TFR) is increasingly becoming a treatment goal for patients with chronic myeloid leukemia (CML) in chronic phase (CP). Although strict criteria guide tyrosine kinase inhibitor (TKI) discontinuation, there exists a knowledge gap in understanding patient and provider experience regarding TFR in real-world clinical practice. Here, we report our TFR experience in patients with CML-CP, treated at an academic center in the Deep South.

Methods: A retrospective chart review was performed to evaluate outcomes of patients with CML-CP at the University of Alabama at Birmingham. The NCCN Version 2.2023 criteria for TKI discontinuation was utilized. Institutional review board approval was obtained.

Results: We identified 204 patients with CML-CP through electronic medical records (EMR) . The median follow-up for the entire population was 95m (range 2-246m). The median age was 54y (range 21-75y) and majority of the patients were females (62%) and non-Hispanic whites (NHWs) (70%). A diagnostic bone marrow biopsy was performed on 59% of the patients. Most of the patients had p210 breakpoint (93%). Frontline therapy mainly consisted of imatinib (42%), dasatinib (32%) and nilotinib (16%).

Out of the 204 patients, 44 (22%) met all the criteria for TKI discontinuation (Table 1). The median age for these patients was 53y (range 20-75y) and majority of the patients were females (68%) and NHWs (68%). Frontline therapy consisted of imatinib (59%), dasatinib (23%) and nilotinib (18%).

Out of the 44 patients eligible for TFR attempt, 35 (80%) were offered TKI discontinuation by their provider whereas 9 (20%) were not. Reasons for not offering TKI discontinuation were not documented in the EMR. Twenty-four out of 35 patients attempted TKI discontinuation. The median time to TKI discontinuation for these patients was 114m (range 45-246m). Frontline therapy consisted of imatinib (n=13), dasatinib (n=7) and nilotinib (n=4) for those that attempted TFR. Ten patients had to resume TKI (imatinib=5, dasatinib=1, nilotinib=4) due to an increasing transcript after a median of 8m (range 2-29m). The remaining 14 patients (58%) remain in TFR to date with a median follow-up of 29m (6-51m).

Eleven patients, eligible for TKI discontinuation, were offered a trial of TFR but did not attempt it. Three patients were satisfied with ongoing therapy and did not want to attempt TKI discontinuation or dose-reduction. Eight patients were hesitant to discontinue therapy and agreed to reduce the dose of the current therapy after discussing with their provider. Seven of those eight patients remain on a reduced TKI dose and 1 had to increase the dose due to an increase in transcript.

Conclusion: In our single-center experience, we report that although most of the patients eligible for TKI discontinuation were offered a TFR attempt by their provider, there remains room for improvement. More than half the patients that attempted TKI discontinuation remain off therapy. Patient preference was the main reason for not attempting TKI discontinuation but there was willingness to attempt dose-reduction. Further studies are needed to understand both patient and provider perspectives regarding TFR to identify opportunities for improvement.