This Phase 3, multicenter, randomized, two-arm, open-label study will include subjects with intermediate or high-risk (as per the DIPSS score) primary myelofibrosis (PMF), postpolycythemia vera myelofibrosis (post-PV MF), or post-essential thrombocythemia myelofibrosis (post-ET MF). This study will be conducted in compliance with International Council for Harmonisation (ICH) Good Clinical Practices (GCPs).~Study design includes:~A 28-day Screening Period~2:1 Randomization to fedratinib or best available therapy (BAT)~Stratification at Randomization according to:~Spleen size by palpation: < 15 cm below left costal margin (LCM) versus ≥ 15 cm below LCM~Platelets ≥ 50 to < 100 x 109/L versus platelets ≥ 100 x 109/L~Refractory or relapsed to ruxolitinib treatment versus intolerant to ruxolitinib treatment~Study Treatment Period (time on study drug plus 30 days after last dose)~Subjects are allowed to crossover from BAT to the fedratinib arm after the Cycle 6 response assessment or before the Cycle 6 response assessment in the event of a confirmed progression of splenomegaly by MRI/CT scan~A Survival Follow-up Period for progression and survival
A Phase 3, multicenter, open-label, randomized study to evaluate the efficacy and safety of fedratinib compared to best available therapy (BAT) in subjects with DIPSS (Dynamic International Prognostic Scoring System)-intermediate or high-risk primary myelofibrosis (PMF), post-polycythemia vera myelofibrosis (post-PV MF), or post-essential thrombocythemia myelofibrosis (post-ET MF) and previously treated with ruxolitinib. The primary objective of the study is to evaluate the percentage of subjects with at least 35% spleen volume reduction in the fedratinib and the BAT arms.