JAK2 and myeloproliferative neoplasm: In this context, momelotinib has recently undergone a Phase I/II clinical trial for myelofibrosis, a fatal myeloproliferative neoplasm driven by the constitutive activation of JAK2/STAT3 pathway frequently caused by a JAK2V617F gain-of-function mutation which involves a valine-to-phenylalanine modification at position 617 [52].