Ruxolitinib (INCB018424) in Participants With Primary Myelofibrosis (PMF), Post Essential Thrombocythemia-myelofibrosis and Post Polycythemia Vera-myelofibrosis (PPV-MF)

Inclusion Criteria:

Diagnosed with PMF, PPV-MF or PET-MF as confirmed by bone marrow biopsy
Discontinuation of all drugs used to treat underlying MF disease at least 14 days prior to baseline visit
INR <= 1.5 or PTT value < 1.5 x upper limit of normal (ULN) at study entry
Hemoglobin level at least 6.5 g/dL at Screening visit
Willingness to be transfused to treat low hemoglobin levels

Exclusion Criteria:

Females who are pregnant, unable to comply with birth control use to avoid becoming pregnant or breastfeeding
Males who cannot comply with birth control use to avoid fathering a child
Platelet count < 50 x10^9/L or absolute neutrophil count (ANC) < 1 x10^9/L at the Screening visit
Inadequate liver or renal function; Intracranial bleeds or invasive malignancy over the previous 2 years - international normalized ratio (INR) laboratory values cannot be > 1.5 x upper limit of normal at study entry.