RAPID AND DEEP RESPONSES WITH ASCIMINIB IN PATIENTS (PTS) WITH CHRONIC MYELOID LEUKEMIA IN CHRONIC PHASE (CML-CP) AFTER ≥2 PRIOR TYROSINE KINASE INHIBITORS (TKIS) IN THE PHASE 3 ASCEMBL STUDY (EHA 2023)
Background: In ASCEMBL, after ≥2 y of follow-up, asciminib (ASC) continued to demonstrate superior efficacy and better safety and tolerability than bosutinib (BOS), with more pts on ASC remaining on and continuing to benefit from therapy over time... Eligible pts with intolerance or treatment failure/lack of efficacy per European LeukemiaNet (ELN) 2013 recommendations were randomized 2:1 to ASC 40 mg twice daily or BOS 500 mg once daily and gave informed consent...Overall MMR rates at wk 96 were higher with ASC than BOS regardless of the last prior TKI received (imatinib, 55.6% vs 14.3%; nilotinib, 40.9% vs 35.7%; dasatinib, 37.1% vs 10.5%; radotinib, 50.0% vs 0%; ponatinib, 20.0% vs 11.8%) and reason for its discontinuation (intolerance [ASC, n=59; BOS, n=22] vs resistance [ASC, n=95; BOS, n=54])... Responses were fast with ASC and continued to deepen over time. Pts who remained on ASC beyond wk 24 could still achieve MMR by later time points. Overall MMR rates at wk 96 were higher with ASC than BOS regardless of the last TKI and reason for its discontinuation; MMR rates were also higher with ASC in pts resistant to all prior 2G TKIs.