Thrombocytopenia in Patients With Myelofibrosis: A Practical Management Guide

Patients with myelofibrosis (MF) frequently develop thrombocytopenia as a consequence of bone marrow fibrosis, splenic sequestration, and myelosuppression from an inflammatory microenvironmental milieu. Thrombocytopenia occurs frequently at diagnosis, worsens with disease progression, is an independent adverse prognostic factor, and limits effective dosing of JAK2 inhibitors. Recently, pacritinib was approved for patients with MF and extreme thrombocytopenia. However, this JAK2/IRAK1 inhibitor is not primarily used to attain improvement in platelet count. In this narrative review, we discuss strategies to specifically address thrombocytopenia in MF patients including immunomodulatory drugs, synthetic androgens, hypomethylating agents and splenectomy, all of which have only modest efficacy in alleviating thrombocytopenia. We also detail transfusion approaches, including diagnostic and therapeutic consideration for platelet transfusion refractoriness. We end by discussing novel therapies, including TGFβ traps and recombinant pentraxin-2, which may increase platelet counts in MF patients. Despite recent therapeutic advancements in MF, there remains a near paucity of agents that can effectively alleviate thrombocytopenia.