CML-428 Real World Data of Treatment Free Remission (TFR) in Patients With Chronic Myeloid Leukemia (CML) Treated at a Tertiary Care Oncology Center in India

Abstract

TFR has emerged as a new treatment goal in treatment of CML. To describe the outcomes of CML patients undergoing treatment free remission (TFR) in clinical practice. Retrospective analysis of CML patients treated from January 2018 to December 2021 who underwent TFR. Tertiary care cancer center Patients: 38 patients who opted for TFR after counselling or tyrosine kinase inhibitor (TKI) stopped due to various reasons in deep molecular response (DMR) were included. 92% were treated with imatinib at diagnosis. Median duration of TKI treatment was 135 months (6-242). 97.5% achieved DMR on TKI and median time from TKI initiation to DMR was 96 months (12-228). Median duration of DMR prior to TKI discontinuation was 41 months (0-67). TKI was discontinued after counselling for TFR in 26 patients (68%) while it was discontinued due to intolerance in 10 patients (29%). Data was analyzed for molecular relapse (MR), survival without molecular relapse (SWMR), TFR duration, and factors affecting MR. At median follow up of 25 months, nine patients (23.7%) had molecular relapse and three patients died. Median SWMR was not reached, and 2-year estimated SWMR was 65.2% (95%CI,47.2-83.2). After censoring for the competing events of death, 2-year cumulative molecular relapse was 26.8% (95%CI, 10.5-43). Median time to MR was 4 months. Of all relapses, 55.5% occurred in the first six months of TFR. Nine patients (23.7%) were restarted on TKI. Two patients with MR were not restarted on TKI as one patient died immediately after MR and another patient was not keen on restarting TKI despite repeated counselling. Median TFR duration was not reached, and 2-year estimated TFR was 73.4% (95%CI, 58.3-88.5). After restart of TKI, median duration to achieve MMR was 6 months (range, 1-17) in patients with molecular relapse. At the time of analysis, molecular disease statuses were DMR, MMR and less than MMR in 23, 10 and 2 patients respectively. TKI can be safely discontinued in real life practice in chronic phase CML patients in DMR and comparable TFR outcomes can be achieved. Grant acknowledgement: None.