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) ≤ 3.0 x ULN
• •Alanine transaminase (ALT) ≤ 3.0 x ULN
• •Alkaline phosphatase ≤ 2.5 x ULN
• •Serum lipase ≤ 1.5 x ULN
• •Participants must have the following laboratory values ≥ Lower Limit of Normal or corrected to within normal limits with supplements prior to randomization: potassium increase of up to 6.0 mmol/L is acceptable if associated with creatinine clearance within normal limits ; calcium increase of up to 12.5 mg/dl or 3.1 mmol/L is acceptable if associated with creatinine clearance\* within normal limits) ; magnesium increase up to 3.0 mg/dL or 1.23 mmol/L if associated with creatinine clearance within normal limits.