European Medicines Agency Approves New Myelofibrosis Treatment Momelotinib for Marketing in the European Union


The marketing authorization application for oral momelotinib in myelofibrosis has been approved by the European Medicines Agency.

The European Medicines Agency (EMA) approved the marketing authorization application for the novel myelofibrosis treatment momelotinib based on data from the phase 3 MOMENTUM trial (NCT04173494) and others, according to a press release from GSK.1

Momelotinib is a new agent with inhibitory ability along the Janus kinase (JAK) 1, JAK2, and activin A receptor type 1 (ACVR1) pathways.1 It was the subject of a new drug application accepted by the FDA earlier this year.

Of note, the FDA is expected to make a decision on momelotinib by June 2023.

Primary findings from the randomized, double-blind MOMENTUM trial showed a total symptom score (TSS) response rate of 24.6% in patients treated with momelotinib vs 9.2% in those treated with danazol (P = .0095) at the end of the 24-week randomized treatment phase. The TSS change from baseline was -9.36 with momelotinib vs -3.13 with danazol (P = .0014), and the respective zero transfusion rates were 35.4% and 16.9% (P = .0012).

The red blood cell transfusion­ independence rate was 30.8% in the experimental group vs 20.0% in the control group (one-sided P = .0064), thereby meeting the end point of non-inferiority.2

A reduction in spleen volume of 25% or greater occurred in 40.0% and 6.2% of patients in the experimental and control groups, respectively (P < .0001). Reductions of 35% or greater, meanwhile, occurred in 23.1% and 3.1%, respectively (P = .0006).2

Patients were administered either momelotinib at 200 mg daily plus placebo or danazol at 600 mg daily plus placebo momelotinib for 24 weeks. Randomization was 2:1 to the experimental (n = 130) and control (n = 65) groups.

A greater proportion of patients completed the 24-week momelotinib treatment (72%; n = 94) than the danazol treatment (58%; n = 38). All patients had prior treatment with the JAK inhibitor ruxolitinib (Opzelura) and 5% had prior treatment with fedratinib (Inrebic).

The most common grade 3 or higher treatment-emergent adverse effects (TEAEs) were thrombocytopenia, affecting 22% and 12% of patients respectively in the experimental and control groups, and anemia, affecting 8% and 11%, respectively.

Infections of grade 3 or greater occurred in 15% of patients receiving momelotinib and 17% of those receiving danazol. Peripheral neuropathy occurred in 4% and 2%, respectively. A smaller proportion of patients discontinued momelotinib (18%) than danazol (23%) due to TEAEs.2

Updated 48-week data is planned for presentation at the upcoming 64th American Society of Hematology Annual Meeting.1


  1. European Medicines Agency accepts marketing authorisation application for momelotinib for the treatment of myelofibrosis. News Release. GSK. December 2, 2022. Accessed December 5, 2022.
  2. Mesa RA, Gerds AT, Vannucchi A, et al. MOMENTUM: phase 3 randomized study of momelotinib (MMB) versus danazol (DAN) in symptomatic and anemic myelofibrosis (MF) patients previously treated with a JAK inhibitor. J Clin Oncol. 2022;40(suppl 16):7002. doi:10.1200/JCO.2022.40.16_suppl.7002
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