Study of Efficacy and Safety of Asciminib in Combination With Imatinib in Patients With Chronic Myeloid Leukemia in Chronic Phase (CML-CP)

Inclusion Criteria:

1. Male or female patients ≥ 18 years of age with a confirmed diagnosis of Chronic
Myeloid Leukemia in chronic phase (CML-CP).

2. Minimum of two years (24 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).

3. BCR-ABL1 levels > 0.01% IS (International Scale) and ≤ 1% IS at the time of study
entry as confirmed with a central assessment at screening; patients must not have
achieved deep molecular response (MR4 IS) at any time during prior imatinib treatment.

4. 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

5. Patients must have the following laboratory values ≥ Lower Limit of Normal or
corrected to within normal limits with supplements prior to randomization: potassium,
magnesium, phosphorus, total calcium (corrected for serum albumin).

Key Exclusion Criteria:

1. Treatment failure according to European Leukemia Network (ELN) criteria 2013 during
imatinib treatment.

2. Known second chronic phase of CML after previous progression to Accelerated Phase
(AP)/Blast Crisis (BC).

3. Previous treatment with any tyrosine kinese inhibitors (TKIs) other than imatinib.

4. History or current diagnosis of ECG abnormalities indicating significant risk or
safety for subjects participating in the study such as:

- History of myocardial infarction, angina pectoris, coronary artery bypass graft
within 6 months prior to randomization

- Concomitant clinically significant arrhythmias

- Resting QTcF ≥ 450 msec (male) or ≥ 460 msec (female) prior to randomization

- Long QT syndrome, family history of idiopathic sudden death or congenital long QT
syndrome, or any of the following:

- Risk factors for Torsades de Pointes

- Concomitant medications with a "known" risk of Torsades de Pointes

- inability to determine the QTcF interval

5. Severe and/or uncontrolled concurrent medical disease that in the opinion of the
investigator could cause unacceptable safety risks or compromise compliance with the
protocol (e.g. uncontrolled diabetes, active or uncontrolled infection, uncontrolled
clinically significant hyperlipidemia and high serum amylase)

6. History of acute pancreatitis within 1 year prior to randomization or past medical
history of chronic pancreatitis.

7. History of other active malignancy within 3 years prior to randomization with the
exception of basal cell skin cancer, indolent prostate cancer and carcinoma in situ
treated curatively.

Other protocol defined inclusion/exclusion may apply.