A Phase 2 Study of the JAK1/JAK2 Inhibitor Ruxolitinib With Chemotherapy in Children With De Novo High-Risk CRLF2-Rearranged and/or JAK Pathway-Mutant Acute Lymphoblastic Leukemia
Primary: Part 1: To evaluate initial safety and tolerability and to define the recommended Part 2 dose (RP2D) of ruxolitinib in combination with multi-agent chemotherapy in children and AYA with de novo HR Ph-like CRLF2-R and/or JAK pathway?mutant B-cell acute lymphoblastic leukemia (B-ALL). Part 2: To determine the efficacy of ruxolitinib in combination with chemotherapy for children and AYA with de novo HR Ph-like CRLF2-R and/or JAK pathway?mutant B-ALL. Secondary: To characterize the safety and potential toxicity of ruxolitinib combined with chemotherapy throughout the course of treatment in children and AYA with de novo HR Ph-like CRLF2-R and/or JAK pathway?mutant B-ALL. Exploratory: To assess the PK of ruxolitinib in combination with chemotherapy in children and AYA with B-ALL. To assess rates of MRD at end-Consolidation in end-Induction MRD+ subjects who are treated with ruxolitinib and chemotherapy To measure PD signaling inhibition and biomarkers of ruxolitinib activity, for correlation with ruxolitinib PK and with efficacy measures. To evaluate the OS of all subjects receiving ruxolitinib in combination with chemotherapy.