Clinical Report: Momelotinib Benefits and Drawbacks in Treatment-Naïve Myelofibrosis

Overview

Momelotinib, a JAK1/2 and ACVR1 inhibitor, offers anemia improvement alongside spleen and symptom control in myelofibrosis (MF). Real-world data, including the MOMGEFIN study, confirm anemia benefits in both JAK inhibitor (JAKi)-exposed and treatment-naïve patients, with manageable safety profiles.

Background

Myelofibrosis is a myeloproliferative neoplasm characterized by splenomegaly, constitutional symptoms, and anemia. JAK inhibitors are standard treatments but often exacerbate anemia. Momelotinib uniquely inhibits ACVR1, reducing hepcidin and improving erythropoiesis, addressing anemia alongside symptom and spleen control. Clinical trials and real-world studies have evaluated momelotinib's efficacy and safety, particularly in patients with transfusion-dependent anemia (TDA).

Data Highlights

Key Findings

• Momelotinib improves anemia in MF patients by inhibiting ACVR1-mediated hepcidin production, enhancing iron availability and erythropoiesis.
• The MOMGEFIN real-world study showed 31% TI at 6 months in transfusion-dependent patients, with slightly higher response in JAKi-exposed versus naïve patients.
• Combination therapy with erythropoietin stimulating agents or danazol improved early anemia response rates compared to momelotinib alone.
• Symptom improvement was observed in 92% of patients, while spleen response was noted in 24%.
• Adverse events were generally manageable, with thrombocytopenia, diarrhea, infections, hepatotoxicity, and peripheral neuropathy being the most common.
• Comparative data suggest momelotinib has a favorable anemia profile versus other JAK inhibitors, especially in treatment-naïve patients.

Clinical Implications

Momelotinib represents a valuable treatment option for MF patients, particularly those with anemia or transfusion dependence. Its dual mechanism addressing both symptom control and anemia may guide JAK inhibitor selection, especially in treatment-naïve patients or those with prior JAKi exposure. Combination with erythropoiesis-stimulating agents may enhance early anemia responses.

Conclusion

Real-world evidence supports momelotinib's efficacy in improving anemia and symptoms in MF, with a manageable safety profile. These findings reinforce its role as a distinct therapeutic option among JAK inhibitors, particularly for patients with anemia-related complications.

References

1. Perez-Lamas et al. 2024 -- MOMGEFIN study on real-world momelotinib use
2. Simons et al. 2023 -- Mechanism of momelotinib in anemia and MF
3. Verstovsek et al. 2019 -- SIMPLIFY-1 and 2 trials
4. Mesa et al. 2021 -- MOMENTUM trial results
5. Tefferi et al. 2018 -- Phase II momelotinib study in TDA