RecruitingDrug trialHEM-iSMART-B: Dasatinib + Venetoclax + Dexamethasone + Cyclophosphamide and Cytarabine in Pediatric Patients With Relapsed or Refractory Hematological MalignanciesHEM-iSMART is a master protocol which investigates multiple investigational medicinal products in children, adolescents and young adults (AYA) with relapsed/refractory (R/R) ALL and LBL. Sub-protocol B is a phase I/II trial evaluating the safety and efficacy of dasatinib + venetocolax in combination with dexamethasone + Cyclophosphamide and cytarabine in children and AYA with R/R ped ALL/LBL whose tumor present with alterations in the MAPK/SRC pathway.