Treatment Discontinuation of First-Line Bosutinib in a Real-World Cohort of Patients With Chronic Myeloid Leukemia: Impact of Hepatic Toxicity.

A multicenter, retrospective study to evaluate the efficacy and safety of first-line bosutinib in patients with newly diagnosed chronic myeloid leukemia (CML) in real-world clinical practice was conducted. Twenty-nine consecutive patients were included between August 2020 and October 2024. The primary endpoint was the cumulative incidence of major molecular response (MMR) at 12 months. The median age was 64 years, and most patients started at a reduced dose. The cumulative incidence of MMR at 12 months was 67.9%, and the overall MMR rate was 20/29 patients (69.0%). The cumulative incidence of MR4 at 12 months was 22.1%, with an overall MR4 rate of 14/29 patients (48.3%). The 24-month overall survival rate was 100%. Bosutinib was discontinued in 14/29 patients (48.3%), and the 24-month cumulative incidence of treatment discontinuation was 51.8%. Dose reduction occurred in 17/29 patients (58.6%) and treatment interruption in 14/29 patients (48.3%). Alanine aminotransferase elevation was the leading cause of discontinuation. First-line bosutinib achieved favorable molecular responses. However, treatment discontinuation due to hepatic toxicity remains a clinical concern in real-world practice.