JAK2 and myelofibrosis: Fedratinib, an oral, JAK2-selective inhibitor, is approved in the USA for the treatment of adult patients with intermediate-2 or high-risk myelofibrosis [3] and in the European Union for the treatment of splenomegaly or symptoms of disease in adult patients with myelofibrosis who are JAK-inhibitor naive or have been treated with ruxolitinib [4].