Safety Study Evaluating Twice-Daily Administration of Momelotinib in Primary Myelofibrosis or Post-Polycythemia Vera or Post-Essential Thrombocythemia Myelofibrosis

"In the Part I dose-escalation phase of the study, subjects will be assigned to dose levels in successive cohorts starting with a dose in the first cohort of 200 mg BID (twice daily with doses taken approximately 12 hours apart. Doses will be escalated by 50 mg BID in successive cohorts of 3 subjects per dose level. Subjects will be evaluated weekly for the first cycle, every 2 weeks during cycle 2, then monthly for 4 cycles for a total of 6 cycles.~In the dose confirmation phase of the study (Part 2), subjects will be evaluated every 2 weeks during the first treatment cycle, and then monthly for 5 cycles for a total of 6 cycles."