Inclusion Criteria:

          -  Documented diagnosis of primary myelofibrosis according to WHO criteria or post PV
             myelofibrosis or post ET myelofibrosis as per IWG-MRT criteria

          -  Age 18-70 years

          -  Intermediate-2/ high-risk disease as per Dynamic IPSS (DIPSS) criteria OR
             Intermediate-1 risk disease with one of the following additional unfavorable features
             known to impact the survival adversely

               1. Red cell transfusion dependency

               2. Unfavorable Karyotype

               3. Platelet count <100 x 109/l

          -  Blasts in the PB and BM ≤10% prior to study enrollment

          -  Availability of a suitable matched related (6/6 or 5/6) or unrelated donor (10/10 or
             9/10 antigen or allele matched).

          -  Able to give informed written consent

          -  ECOG Performance status of 0-2.

          -  Life expectancy >3 months

          -  Off all MF-directed therapy including investigational agents for at least 2 weeks
             prior to study enrollment and recovered from all toxicities*

          -  Adequate organ function

               -  Adequate renal function - creatinine <1.5 x IULN

               -  Adequate hepatic function - AST/ALT <2.5 x IULN, Total Bilirubin <1.5 x IULN

               -  Adequate hematopoietic function - Platelet ≥50 x 109/l and ANC ≥1.0 x 109/l

               -  LVEF >40% (MUGA or echocardiogram) Normal per Institutional standard

               -  Adequate pulmonary function with DLCO >50%

                    -  A patient who has been on stable dose of Ruxolitinib and has received
                       ruxolitinib ≤6 months prior to the study entry will be considered
                       potentially eligible for the study with the caveat that there is no evidence
                       of loss of response (>5cm increase in spleen size from the nadir).

        Exclusion Criteria:

          -  Any previous JAK2 inhibitor treatment prior to study enrollment, with the exception of
             Ruxolitinib

          -  Hypersensitivity to JAK inhibitor

          -  Clinical or laboratory evidence of cirrhosis

          -  Prior allogeneic transplant for any hematopoietic disorder

          -  >20% blast in the PB or BM prior to HCT or had leukemic transformation (>20% blasts in
             PB or BM any time prior to HCT)

          -  Syngeneic donor

          -  Cord Blood transplant

          -  Active uncontrolled infection

          -  H/o another malignancy within 5-years of date of HCT except h/o basal cell or squamous
             cell carcinoma of skin or PV or ET

          -  Known HIV positive

          -  Pregnancy at the time of BMT

          -  Any other concurrent illness which in investigator's opinion puts the patient at
             excessive risk of treatment related toxicities

          -  Unable to give informed consent

          -  Active infection with hepatitis A,B or C virus

          -  Subjects who require therapy with a strong CYP3A4 inhibitor prior to enrollment to
             this study