Ruxolitinib Phosphate and Azacytidine in Treating Patients With Myelofibrosis or Myelodysplastic Syndrome/Myeloproliferative Neoplasm

PRIMARY OBJECTIVES: I. To determine the efficacy of the combination of RUX (ruxolitinib phosphate) with AZA (azacytidine) in patients with myelofibrosis (MF) (primary myelofibrosis, post polycythemia vera myelofibrosis, or post essential thrombocythemia myelofibrosis \[PMF, post- PV MF, or post - ET MF\]) in achieving objective improvements in disease status. II. To determine the efficacy of the combination of RUX + AZA in patients with myelodysplastic syndromes/myeloproliferative neoplasms (MDS/MPN) including chronic myelomonocytic leukemia (CMML), atypical chronic myeloid leukemia (breakpoint cluster region \[BCR\]-c-abl oncogene 1, non-receptor tyrosine kinase \[ABL1\] negative: aCML), and myelodysplastic syndromes/myeloproliferative neoplasms, unclassifiable (MDS/MPN-U), in achieving objective improvements in disease status. SECONDARY OBJECTIVES: I. To determine the safety of the RUX + AZA combination in patients with MF and MDS/MPN. TERTIARY OBJECTIVES: I. To explore time to response (TTR) and duration of response (DOR). II. To explore the effect of the combination on anemia and transfusion dependence in patients with MF and MDS/MPN. III. To explore the impact of baseline mutational profile on International Working Group (IWG)-Myeloproliferative Neoplasms Research and Treatment (MRT) response and overall survival in patients with MF and MDS/MPN. IV. To explore the impact of baseline anemia on overall survival in patients with MF and MDS/MPN. OUTLINE: Patients are assigned to 1 of 2 treatment arms. ARM I (MF): Patients with MF receive ruxolitinib phosphate orally (PO) twice daily (BID) on days 1-28. Beginning course 4, patients also receive azacytidine subcutaneously (SC) or intravenously (IV) for 5 days. Treatment repeats every 28 days for 15 courses in the absence of disease progression or unacceptable toxicity. ARM II (MDS/MPN): Patients with MDS/MPN receive ruxolitinib phosphate and azacytidine as in Arm I. After completion of study treatment, patients are followed up for 30 days and up to 5 years.