Asciminib Provides Better Efficacy and Favorable Safety and Tolerability Against Investigator‐Selected Tyrosine Kinase Inhibitors in East Asian Patients With Newly Diagnosed Chronic Myeloid Leukemia: Results From a Subgroup Analysis of the Pivotal

ABSTRACT

ASC4FIRST ( ClinicalTrials.gov NCT04971226) is a pivotal phase 3 clinical trial comparing the efficacy and safety of asciminib vs. standard of care (SoC) tyrosine kinase inhibitors (TKIs) in newly diagnosed patients with chronic myeloid leukemia in chronic phase (CML‐CP). The study demonstrated superior efficacy and a favorable safety profile for asciminib vs. all current SoC TKIs; this subgroup analysis involved 138 patients from East Asian sites enrolled in ASC4FIRST. Patients were randomized to receive either asciminib or investigator‐selected TKIs (IS‐TKIs: imatinib, bosutinib, dasatinib, or nilotinib) following stratification by risk category and prerandomization‐selected TKI (imatinib or second‐generation TKI). Consistent with non‐East Asian patients, asciminib showed better efficacy in East Asian patients, with a major molecular response (MMR) rate at Week 48 and Week 96 of 64.9% and 77.0% compared to 45.3% and 57.8% for all IS‐TKIs combined, respectively (common treatment difference: 19.5% and 20.0%, respectively). Similar results were obtained for patients with imatinib as the prerandomization‐selected TKI (MMR rate at Week 48 and Week 96: 67.9% and 78.6% for asciminib compared to 30.8% and 46.2% for imatinib, respectively; common treatment difference: 36.5% and 32.7%, respectively). Asciminib also showed a favorable safety profile in East Asian patients, with lower rates of Grade ≥ 3 adverse events (AEs) and AEs leading to discontinuation compared to IS‐TKIs (41.9% vs. 54.0% and 2.7% vs. 9.5%, respectively), consistent with the results from non‐East Asian patients. These findings support the use of asciminib as a first‐line treatment option for East Asian and non‐East Asian patients with CML‐CP.