Peritransplant Ruxolitinib for Patients With Primary and Secondary Myelofibrosis

Inclusion Criteria: * Age \>= 18 years * JAK INHIBITOR ADMINISTRATION INCLUSION: (PART I) * Disease criteria: * Diagnosis of primary myelofibrosis (PMF) as defined by the 2016 World Health Organization classification system or diagnosis of secondary myelofibrosis (MF) as defined by the International Working Group (IWG) for Myeloproliferative Neoplasms Research and Treatment criteria * Patients meeting the criteria for intermediate-1, intermediate-2 or high-risk disease by Dynamic International Prognostic Scoring System (DIPSS) or DIPSS plus * Ability to understand and the willingness to sign a written informed consent document * Patient must be a potential hematopoietic stem cell transplant candidate as assessed by the consenting physician * Patient must be willing to start ruxolitinib within a 6-month time period * ALLOGENEIC STEM CELL TRANSPLANT INCLUSION: (PART II) * Meeting criteria for part 1, as above, at time of initiation of ruxolitinib, including the ability to understand and willingness to sign a written informed consent. Patients arriving to our institution for transplant and not enrolled in part 1 may still be enrolled in part 2 if part 1 criteria are met. These patients will have part 1 endpoints transcribed from medical records * Received ruxolitinib for at least 8 weeks immediately prior to conditioning and be willing to continue until 9-12 months post-transplant as tolerated * Performance status score: Karnofsky \>= 70 * Calculated creatinine clearance u…