In accordance with anterior published work, Fedratinib (a selective JAK2 inhibitor for which clinical studies have been hindered because of its toxicity) also decreased splenomegaly without affecting fibrosis in this TPOhigh murine model, whereas it impaired fibrosis in the post-polycythemia vera  myelofibrosis murine model51, 52. This evidence concerns the gene JAK2 and acquired polycythemia vera.