The aim of this study is to support development of asciminib in the pediatric population (1 to \< 18 years) with Ph+ CML-CP. The study will evaluate the efficacy and safety of asciminib in pediatric formulation (weigh-based dose, fed state) or adult formulation (fasted) in newly diagnosed and resistant or intolerant Ph+ CML-CP with or without T315I mutation.
Signed informed consent must be obtained prior to participation in the study.
Male or female participants 1 and < 18 years of age at study enrollment
Diagnosis of CML-CP (Apperley et al 2025) with cytogenetic confirmation of Philadelphia positive (Ph+) chromosome
At three months after the initiation of therapy: BCR::ABL1 ratio > 10% IS (if confirmed within 1-3 months)
Known second chronic phase (CP) of CML after previous progression to Accelerated Phase (AP)/Blast Phase (BP).
Previous treatment with a hematopoietic stem-cell transplantation.
Patient planned to undergo allogeneic hematopoietic stem cell transplantation
Known presence of a BCR::ABL1 mutation with known resistance to study treatment in accordance with the most recent public version of international CML clinical guidelines (e.g. NCCN CML treatment guidelines v 1.2026 and Apperley et al 2025) any time prior to study entry