Postmarketing surveillance study of asciminib in patients with resistant/intolerant chronic myeloid leukemia in Japan

Following asciminib's initial approval in Japan for chronic myeloid leukemia (CML) resistant or intolerant to previous therapy, this all-patient, postmarketing surveillance study was initiated. Predefined safety specifications, overall safety, and effectiveness were assessed for 48 weeks from asciminib initiation (safety analysis set, n = 523). The approved daily dose of asciminib (80 mg [40 mg twice daily]) was most frequently used (63.9%) and not exceeded. Discontinuations (28.5%) were primarily due to adverse events (18.2%), including disease progression. Incidences of the safety specifications myelosuppression, pancreatitis, QT interval prolongation, infections, vascular occlusive events, and photosensitivity were 8.6%, 4.4%, 2.5%, 1.3%, 0.2%, and 0%, respectively, with low rates of treatment discontinuation for these events. There were no notable trends in the rates or types of adverse drug reactions in patients aged ≥ 65 years or with concurrent renal impairment, hepatic impairment, or cardiac dysfunction. The cumulative major molecular response rate was 61.2% by week 48 and was not affected by age (≥ 65 years) or comorbidities. Cumulative MR4.0 and MR4.5 rates by week 48 were 42.3% and 26.5%, respectively, with some patients harboring baseline BCR::ABL1 mutations showing these responses. These real-world outcomes support the safety and effectiveness of asciminib for patients with resistant/intolerant CML.