Inclusion Criteria:

          -  Pathologically confirmed diagnosis of myelodysplastic syndrome (MDS) or acute myeloid
             leukemia (AML) with >= 5% myeloblasts in either bone marrow or peripheral blood felt
             to be transformed out of an MPN as defined by the 2016 World Health Organization
             criteria, consisting of polycythemia vera, essential thrombocythemia, primary
             myelofibrosis, secondary myelofibrosis, MPN-unclassifiable, or 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 [SCCA] lab). If it is low, it may be repleted but should be rechecked and
             demonstrated to normalize prior to initiation of therapy

          -  Patient is considered a potential transplant candidate. The attending/treating
             physician will determine transplant candidacy at the time of consent

          -  The use of hydroxyurea prior to study registration is allowed. Patients with
             symptoms/signs of hyperleukocytosis, white blood count (WBC) > 100,000/uL, or with
             concern for other complications of high tumor burden or leukostasis (e.g. hypoxia,
             disseminated intravascular coagulation) can be treated with leukapheresis or may
             receive up to 2 doses of cytarabine (up to 500 mg/m^2 /dose) anytime prior to
             enrollment

          -  Capable of providing valid informed consent

        Exclusion Criteria:

          -  Previous treatment with chemotherapy (e.g. hypomethylating agents or cytarabine-based
             regimens) for MPN progressed to MDS or AML. Prior temporary measures to control blood
             counts is allowed. Prior treatment with hydroxyurea, interferons or JAK inhibitor
             therapy is allowed

          -  Active systemic fungal, bacterial, viral, or other infection, unless disease is under
             treatment with anti-microbials and/or controlled or stable (e.g. if specific,
             effective therapy is not available/feasible or desired [e.g. chronic viral hepatitis,
             human immunodeficiency virus (HIV)])

          -  Known hypersensitivity to any study drug

          -  Females who are pregnant or breastfeeding

          -  Treatment with any other anti-MDS/leukemia investigational agent within 2 weeks of
             start of study drugs

          -  For patients planning to receive fedratinib: concurrent use of strong and moderate
             CYP3A4 inducers or dual CYP3A4 and CYP2C19 inhibitors that cannot be discontinued

          -  For patients planned to receive ruxolitinib AND platelets < 50,000/mm^2: concurrent
             use of a strong CYP3A4 inhibitor that cannot be discontinued