Venetoclax, Ponatinib, and Dexamethasone in Participants With Philadelphia Chromosome or BCR-ABL Positive Relapsed or Refractory Acute Lymphoblastic Leukemia or Chronic Myelogenous Leukemia

Inclusion Criteria: * Patients with relapsed/refractory Ph-positive ALL or lymphoid blast phase CML (either t(9;22) and/or BCR-ABL1 positive by fluorescent in situ hybridization or polymerase chain reaction), including prior therapy with at least one Bcr-Abl tyrosine kinase inhibitor * Performance status =\< 3 Eastern Cooperative Oncology Group (ECOG scale) * Total serum bilirubin =\< 1.5 x upper limit of normal (ULN), unless due to Gilbert's syndrome, hemolysis or the underlying leukemia approved by the principal investigator (PI) * Alanine aminotransferase (ALT) =\< 1.5 x ULN, unless due to the underlying leukemia approved by the PI * Aspartate aminotransferase (AST) =\< 1.5 x ULN unless due to the underlying leukemia approved by the PI * Creatinine clearance \>= 30 mL/min * Serum lipase and amylase =\< 1.5 x ULN * Ability to swallow * Signed informed consent Exclusion Criteria: * Prior history of treatment with venetoclax. Prior ponatinib is allowed * Active serious infection not controlled by oral or intravenous antibiotics (e.g. persistent fever or lack of improvement despite antimicrobial treatment) * History of acute pancreatitis within 1 year of study or history of chronic pancreatitis * Uncontrolled hypertriglyceridemia (triglycerides \> 450 mg/dL) * Active secondary malignancy that in the investigator's opinion will shorten survival to less than 1 year * Active grade III-V cardiac failure as defined by the New York Heart Association criteria * Clinically signific…