New Drug Application Accepted by FDA for Momelotinib in Myelofibrosis With Anemia

Based on results from the phase 3 MOMENTUM trial, the FDA has accepted a new drug application of momelotinib for patients with myelofibrosis.

The FDA has accepted a new drug application for momelotinib for patients who have myelofibrosis with anemia, according to a press release from the drugs developer GSK.1

The acceptance is based on results from the phase 3 MOMENTUM trial (NCT04173494), which assessed the agent vs danazol in a population of symptomatic patients previously treated with a JAK inhibitor. The trial met both primary and secondary end points of total symptom score, transfusion independence, and splenic response rate.2 The Prescription Drug User Fee Act is set for June 16, 2023.

Results from the trial were presented at the 2022 American Society of Clinical Oncology (ASCO) Annual Meeting. A total of 195 patients enrolled and randomly assigned 2:1 to receive either momelotinib (n = 130) at 200 mg daily plus placebo or danazol (n = 65) at 600 mg per day plus placebo. At week 24, patients were able to crossover to the momelotinib.

At 24 weeks, 72.3% of patients in the momelotinib arm completed treatment vs 58.5% in the danazol arm, while 70.8% vs 61.5% in each respective group entered the momelotinib open-label expansion. Discontinuation of treatment was necessary in the momelotinib arm because of adverse effects (AEs; n = 16), patient decision (n = 6), insufficient efficacy (n = 6), death (n = 4), leukemic transformation (n = 2), were lost to follow-up (n = 1), or disease progression (n = 1). In the danazol arm, discontinuation occurred because of AEs (n = 11), patient decision (n = 5), death (n = 3), insufficient efficacy (n = 3), disease progression (n = 2), and leukemic transformation (n = 2), and investigator discretion (n = 1).

In terms of splenic response rate at 24 weeks, 40.0% (95% CI, 31.51%-49.95%) of patients in the momelotinib arm had a 25% reduction vs 6.2% (95% CI, 1.70%-15.01%) in the danazol arm (P <.0001). Moreover, a 35% reduction was observed in 23.1% (95% CI, 16.14%-31.28%) in the momelotinib arm and 3.1% (95% CI, 0.37%-10.68%) in the danazol arm (P = .0006). In the momelotinib arm at baseline, the transfusion independence rate was 13% and 31% at 24 weeks compared with 15% and 20% in the danazol arm, respectively (P = .0064).

AEs of grade 3 or higher were observed in 53.8% vs 64.6% and serious AEs were observed in 34.6% vs 40.0% of patients in the momelotinib and danazol arms, respectively. The most common grade 3 or higher AEs in each arm, respectively, was anemia (60.8% vs 75.4%), thrombocytopenia (27.7% vs 26.2%), neutropenia (12.3% vs 9.2%), acute kidney injury (3.1% vs 9.2%), and dyspnea (2.3% vs 1.5%).


  1. US FDA accepts new drug application for GSK’s momelotinib for the treatment of myelofibrosis. News Release. FDA. August 17, 2022. Accessed August 17, 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