| Inclusion Criteria: | 1) Must be at least 18 years of age with life expectancy of at least 12 weeks
2) Must be diagnosed with PMF or Post-PV/ET MF, irrespective of JAK2 mutation status.
3) Patients with myelofibrosis requiring therapy, including those previously treated by myelofibrosis directed therapy who have subsequently relapsed or are refractory; or, if newly diagnosed, should be intermediate or high risk according to Lille (Dupriez) Scoring System (Dupriez et al, 1996), (adverse prognostic risk factors are: Hgb < 10g/dL, WBC < 4 or > 30x10^9/L; risk group: 0 factor=low, 1 factor = intermediate, 2 factors = high); or with symptomatic splenomegaly that is > 10 cm below costal margin.
4) Must have palpable spleen measuring 10 cm or greater below the costal margin (Patients in Part 3, Group III only). However, with permission of the sponsor, patients with spleen size of ≤ 10 cm, or in rare cases, with prior splenectomy, but ongoing hepatomegaly may be enrolled in Part 3, Group III.
5) Have adequate bone marrow reserve as demonstrated by: a) absolute neutrophil count (ANC) that is > 1500/µL b)platelet count that is > 100,000/µL without the assistance of growth factors.
6) Have an Eastern Cooperative Oncology Group (ECOG) performance status of 0, 1 or 2, in Part 1, Part 2, Part 3 Group l and ll and status of 1 or 2 in Part 3 Group lll.
7) Have adequate liver and renal function. a)Total bilirubin ≤ 2.0 mg/dL. b)Alanine aminotransferase (ALT) ≤ 2.5x institutional upper limit of normal (ULN) or ≤ 5x institutional upper limit of normal if the liver is involved by malignancy as judged by the treating physician and the Investigator with documented justification. c)Creatinine ≤ 2.5 mg/dL.
8) A female of childbearing potential must have a negative serum pregnancy test at screening.
9) Females will be either postmenopausal for at least 1 year with documented FSH > 30 IU/L or surgically sterile for at least 3 months OR females of child-bearing potential who must agree to take appropriate precautions to avoid pregnancy from screening through follow-up. For all females, the pregnancy test result must be negative at Screening. Males must agree to take appropriate precautions to avoid fathering a child from screening through follow-up.
10) Is able to comprehend and is willing to sign an informed consent form. |