GSK regulatory submission for myelofibrosis medicine momelotinib accepted for review by Japanese regulator

Momelotinib has a differentiated mechanism of action, with inhibitory ability along three key signalling pathways: Janus kinase (JAK) 1, JAK2, and activin A receptor, type I (ACVR1). Inhibition of JAK1 and JAK2 may improve constitutional symptoms and splenomegaly. Additionally, inhibition of ACVR1 leads to a decrease in circulating hepcidin, which is elevated in myelofibrosis and contributes to anaemia.

Myelofibrosis is a blood cancer that can lead to splenomegaly (enlarged spleen); constitutional symptoms such as fatigue, night sweats, and bone pain; and severely low blood counts, including anaemia and thrombocytopenia. About 70% of patients diagnosed with primary myelofibrosis and about half of patients diagnosed with secondary myelofibrosis in Japan have moderate to severe anaemia at the time of diagnosis, and nearly all patients are estimated to develop anaemia over the course of the disease. Patients who are transfusion dependent have a poor prognosis and shortened survival.

Momelotinib is not currently approved in any market.

MOMENTUM was a global, randomised, double-blind phase III clinical trial of momelotinib (MMB) versus danazol (DAN) in patients with myelofibrosis who were symptomatic and anaemic and had been previously treated with an approved JAK inhibitor. The MOMENTUM trial met all its primary and key secondary endpoints, with respect to splenic response, constitutional symptoms and transfusion independence. Results from the 24-week treatment period were presented at the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting and subsequently published in The Lancet.