Study of Efficacy and Safety of Asciminib in Combination With Imatinib in Patients With Chronic Myeloid Leukemia in Chronic Phase (CML-CP) Who Have Been Previously Treated With Imatinib and Have Not Achieved Deep Molecular Response.

Inclusion Criteria: * Male or female patients ≥ 18 years of age with a confirmed diagnosis of CML-CP. * Minimum of one year (12 calendar months) treatment with imatinib first line for CML-CP (patients have to be on imatinib 400 mg QD at randomization and had no dose change in the past three months). For Korea only: (i) a minimum of one year (12 calendar months) of prior treatment with imatinib for patients with BCR::ABL1 levels \> 0.1%, ≤ 1% IS at the time of randomization. (ii) a minimum of two years (24 calendar months) of prior treatment with imatinib for patients with BCR::ABL 1 levels \> 0.01%, ≤ 0.1% IS at the time of randomization. * BCR::ABL1 levels \> 0.01% IS (International Scale) and ≤ 1% IS at the time of randomization as confirmed with a central assessment at screening; patients must not have achieved deep molecular response (MR4 IS) confirmed by 2 consecutive tests at any time during prior imatinib treatment. An isolated, single test result with BCR::ABL1 levels \< 0.01 % (MR4 IS) is allowed, however, it should not have been observed within the 9 months prior to randomization * Patient must meet the following laboratory values before randomization: * Absolute Neutrophil Count ≥ 1.5 x 10E9/L * Platelets ≥ 75 x 10E9/L * Hemoglobin ≥ 9 g/dL * Serum creatinine \< 1.5 mg/dL * Total bilirubin ≤ 1.5 x ULN (Upper Limit of Normal) except for patients with Gilbert's syndrome who may only be included with total bilirubin ≤ 3.0 x ULN * Aspartate transaminase (AST) ≤ 3.…