This study investigates treatments for Philadelphia chromosome positive acute lymphoblastic leukemia (ALL), a type of cancer affecting the blood and bone marrow. The purpose of this study is to examine the effectiveness of combining an investigational medication with different chemotherapy approaches to improve disease-free survival in children with standard risk ALL. The investigational medication is used alongside either a high-risk Children's Oncology Group (COG)/Berlin-Frankfurt-Munster (BFM) ALL chemotherapy backbone or a more intensive European (Es)PhALL chemotherapy backbone.

Participants will undergo specific procedures, including receiving the investigational medication and chemotherapy as part of their treatment plan. Chemotherapy involves using drugs to stop the growth of cancer cells, either by killing the cells or by stopping them from dividing. The study will help determine which combination is more effective for patients.

• Who can participate: Children newly diagnosed with Philadelphia chromosome positive acute lymphoblastic leukemia can participate. They must have definitive evidence of BCR-ABL1 fusion by karyotype, FISH, or RT-PCR, not have started treatment with certain medications, and meet specific health criteria. Those with Down syndrome, a history of chronic myelogenous leukemia, or certain heart conditions are excluded.
• Study details: Participants will receive an investigational medication alongside chemotherapy. Some will receive the medication with a standard chemotherapy regimen, while others will receive it with a more intensive regimen.