The purpose of this study is to investigate the effectiveness of an investigational medication compared to another treatment when used as the first therapy along with reduced-intensity chemotherapy in patients with newly diagnosed Philadelphia chromosome-positive acute lymphoblastic leukemia (Ph+ ALL). Ph+ ALL is a type of cancer that affects the blood and bone marrow and is characterized by the presence of an abnormal chromosome called the Philadelphia chromosome.

Participants in this study will receive either the investigational medication or the other treatment, both combined with chemotherapy. The study will measure how well each treatment works by looking at the number of patients who achieve a complete response that is negative for minimal residual disease (MRD) after the initial treatment phase. MRD-negative means no signs of cancer cells are found in the bone marrow.

• Who can participate: Participants must have been newly diagnosed with Philadelphia chromosome-positive or BCR-ABL1-positive acute lymphoblastic leukemia and must not have active serious infections requiring antibiotics within 14 days before starting the study medication.
• Study details: Participants will be randomly assigned to receive either the investigational medication or another treatment, both combined with chemotherapy. A placebo, which is an inactive substance that looks like the investigational medication but does not contain any medicine, may be used in the study.