Clinical Utility of Fedratinib in Myelofibrosis

Myelofibrosis (MF) is a clonal hematologic malignancy characterized by bone marrow fibrosis, extramedullary hematopoiesis, splenomegaly, and constitutional symptoms with a propensity towards leukemic transformation. Constitutive activation of the JAK/STAT pathway is a well-described pathogenic feature of MF. Allogeneic stem cell transplant is the only curative therapy, but due to high morbidity and mortality this option is not available for most patients. There are two approved targeted therapy options for MF, ruxolitinib and fedratinib. In this review, we discuss the clinical utility of fedratinib in the myelofibrosis treatment paradigm. Fedratinib has shown impressive pre-clinical and clinical efficacy in patients with untreated MF as well as in those with ruxolitinib intolerance and those with relapsed/refractory MF. Here, we review the pre-clinical and clinical trials that led to the approval of fedratinib, and the ongoing late-phase trials. We highlight several areas regarding the clinical utility of fedratinib that remain unanswered. We discuss the limitations of fedratinib and address areas that are understudied and require further clinical evaluation and research. The approval of fedratinib has provided a significant expansion to the very limited treatment armamentarium available to patients with MF.