Decitabine With Ruxolitinib, Fedratinib or Pacritinib for the Treatment of Accelerated/Blast Phase Myeloproliferative Neoplasms

Inclusion Criteria: * Age \>= 18 years * History of MPN as defined by the 2016 World Health Organization criteria, with now pathologically confirmed \>= 5% blasts in the bone marrow or peripheral blood. Prior MPNs could include polycythemia vera, essential thrombocythemia, primary myelofibrosis, secondary myelofibrosis, MPN unclassifiable, MDS/MPN overlap * Outside diagnostic material is acceptable as long as peripheral blood and/or bone marrow slides are reviewed at the study institution by pathology. Flow cytometric analysis of peripheral blood and/or bone marrow should be performed according to institutional practice guidelines * Eastern Cooperative Oncology Group (ECOG) performance status 0-2 or Karnofsky \>= 60% * Serum creatinine clearance \>= 50 ml/min calculated by the Cockcroft-Gault Equation (assessed within 14 days of study day 1) * Total bilirubin =\< 3 unless due to Gilbert's disease or hemolysis (total bilirubin \> 3 is allowable if thought due to Gilbert's disease, hemolysis, or MPN disease) (assessed within 14 days of study day 1) * Aspartate aminotransferase (AST)/alanine aminotransferase (ALT) \< 3 x upper limit of normal (ULN) unless thought to be due to MPN disease process (AST/ALT \> 3 is allowable if thought due to MPN disease) (assessed within 14 days of study day 1) * For patient receiving fedratinib, thiamine level should be above the laboratory lower limit of normal (\>= 70 nmol/L in the University of Washington \[UW\]/Seattle Cancer Care Alliance \…