A Study on the Tolerability, Safety and Effectiveness of Asciminib in Patients With Philadelphia Chromosome-positive Chronic Myeloid Leukemia in the Chronic Phase in Germany

Inclusion criteria: 1. Written informed consent must be obtained before participation in the study/prior to any study-related documentation. 2. Adult patients (≥18 years of age) with a confirmed diagnosis of Ph+ CML-CP. The presence of the Philadelphia chromosome may alternatively be confirmed by molecular detection of a BCR::ABL1 fusion gene/transcript (e.g., by reverse transcription polymerase chain reaction (RT-PCR)), in accordance with the World Health Organization (WHO) 2022 classification. 3. Patients who are either newly diagnosed or have received treatment with exactly one prior TKI. Prior TKI treatment is only permitted for patients in the Asciminib Cohort. Patients in the comparator cohorts (imatinib, dasatinib, bosutinib, nilotinib) must be newly diagnosed and must not have received any prior TKI treatment. 4. Patients for whom the treating physician has made a clinical decision to initiate treatment with asciminib or another TKI (imatinib, dasatinib, bosutinib, nilotinib) as part of routine care. The clinical decision for treatment must have been made prior to enrollment. Treatment must not have started more than 14 days before study inclusion, and treatment may also begin after baseline assessment. 5. Patients willing to participate in routine follow-up visits and complete patient-reported outcome questionnaires over the course of the study. Exclusion criteria: 1. Patients with contraindications to their respective chronic myeloid leukemia (CML) treatment as per the applicable Summary of Product Characteristics (SmPC) and relevant national treatment guidelines (e.g. Onkopedia CML), as well as additional disease- or treatment-related characteristics associated with distinct clinical scenarios that differ from the intended study population, including situations with specific treatment requirements or limited comparability, in which reliable interpretation of study outcomes may not be feasible, including the following asciminib specific considerations: * In first- or second-line treatment: presence of BCR::ABL1 fusion transcripts lacking exon a2 (e.g. e13a3, e14a3, e1a3). * In second-line treatment: * known BCR::ABL1 mutations associated with partial or complete resistance to asciminib (e.g. M244V, F359I/V/C). * presence of the BCR::ABL1 T315I mutation, regardless of eligibility for treatment according to SmPC (e.g., specific indication and dosing regimens). 2. Patients receiving or planned to receive asciminib or other TKIs outside the approved label (off-label use), including use in unapproved dosing regimens or frequency not covered by the respective SmPC. 3. Patients currently participating in an interventional clinical trial. 4. Patients unable or unwilling to provide written informed consent. 5. Patients who are unable to reliably complete patient-reported outcome questionnaires due to cognitive or language limitations relevant to the study assessments. 6. Patients for whom long-term follow-up is not feasible due to expected relocation or other logistical constraints. 7. The restriction to a maximum of one prior ATP-competitive TKI applies exclusively to patients treated with asciminib. Patients in the comparator cohorts (imatinib, dasatinib, bosutinib, nilotinib) must be TKI-naïve and are included at the start of their first-line TKI therapy and are not eligible if they have received any prior TKI treatment.