Real world evidence on treatment efficacy and safety of tyrosine kinase inhibitors in patients with chronic myeloid leukemia.

Abstract

e18570 Background: Chronic myeloid leukemia (CML) treatment was revolutionaized with the introduction of tyrosine kinase inhibitors (TKIs) targeting BCR-ABL1. Imatinib, a first generation BCR-ABL1 TKI was the first agent to be approved, followed by second generation agents; nilotinib, dasatinib and bosutinib all of which are recommended as first line therapies for chronic phase CML. Real world data assessing the major molecular response (MMR) rates and safety profile of TKIs in Saudi Arabia has not been reported, this study aims to assess treatment outcomes in patients with CML in a large cancer center in Saudi Arabia. Methods: Descriptive real world data report was conducted through electronic medical record review. We included all adult patients with CML who received TKIs from 2015- 2023. Disease risk stratification was performed through sokal score, patient comorbidities were assessed using the charlson comorbidity index (CCI) score, MMR was assessed through BCR-ABL1 level at treatment milestones (3, 6 and 12 months). Safety profile for each patient was assessed through screening for adverse events and grading adverse events based on common terminology criteria for adverse events (CTCAE). Results: We included 113 patients, median age was 44 years (IQR 32-54), 56.6% were females, 48% had high risk disease based on sokal score. Majority of patients had low cormobidities, 50.4% had a CCI score of 2 and 78.7% had an ECOG performance status of 0-1. Imatinib was the most frequently utilized medication accounting for 54.9% of MMRs, followed by dasatinib (24.7%), nilotinib (15.9%) and finally bosutinib and asciminib each accounting for 1.8% of achieved MMRs. At the 3 month mark, 73.5% of patients achieved MMR and that number increased to 85.1% at the 6 month mark. At 12 months, 18% of patients experienced loss of response. The most common therapy switch was done with imatinib (67.7%), average time to therapy change with imatinib was 32 months, dasatinib represented the most frequent second line therapy (58%) with dose range of 50-100 mg. Anemia (29%), thrombocytopenia (12.7%), neutropenia (16.3%) and rash (10.9%) were the most frequently reported adverse events, majority of reported adverse events were grades 1 and 2. Conclusions: This report highlights a high response rate among our patients with 85% achieving complete response within the first 6 months with an acceptable side effect profile. A loss of reponse is observed at the 12 month mark which could be attributed to the use of imatinib in patients with high risk disease.