Momelotinib for the treatment of myelofibrosis

Introduction: The abnormally activated JAK-STAT pathway plays a central role in the pathogenesis of BCR/ABL-negative myeloproliferative neoplasms (MPNs), simultaneously providing a theoretical and clinical basis for the development of small-molecule compounds targeting JAK. The first approved drug, ruxolitinib, demonstrated a rapid and durable improvement of symptoms and splenomegaly accompanied with better overall survival in myelofibrosis (MF) patients. However, ruxolitinib-related adverse effects and resistance are limitations, so there is an urgent need to develop new JAK inhibitors to retain the efficacy of ruxolitinib and avoid its deficiency. Areas covered: This review discusses the preclinical and clinical studies of momelotinib (MMB) aiming to gain a deeper understanding of the advantages and clinical limitations of this drug. Expert opinion: The clinical trial data available thus far indicate that MMB is not inferior to ruxolitinib in spleen response and symptoms response, with the improvement of anemia surprising. The only obstacle that may slowdown its approval is treatment-emerged peripheral neuropathy (PN). If we can minimize MMB's treatment-related PN by administration optimization, MMB promises to be a good choice of individualized treatment for MF patients mainly manifesting as anemia.