# Momelotinib

Source: https://onco.cc/drugs/momelotinib/  
OnCo record `momelotinib` (Treatment). Data CC BY-NC 4.0, attribute "Data from OnCo (onco.cc)"; commercial use needs a licence.

## TL;DR

Momelotinib is the JAK inhibitor designed for anaemic myelofibrosis patients: it can improve haemoglobin while shrinking the spleen.

## Summary

Momelotinib inhibits JAK1 and JAK2 to shrink the spleen and relieve symptoms, and additionally blocks ACVR1 (ALK2), which lowers hepcidin and frees iron for red-cell production. That second action is why it was developed for myelofibrosis patients whose anaemia rules out or limits other JAK inhibitors. MOMENTUM (2023) compared it with danazol in symptomatic anaemic patients after a prior JAK inhibitor: symptom response was superior, transfusion independence non-inferior, and spleen response better. The earlier SIMPLIFY-1 and SIMPLIFY-2 trials against ruxolitinib and best available therapy built the anaemia signal. It was approved in the US in 2023 and the EU in 2024 for myelofibrosis with anaemia. For a newcomer, momelotinib is the JAK inhibitor chosen when low haemoglobin is the dominant problem.

## Fields

- Kind: Treatment
- Status: approved
- Last checked: 2026-09-08
- Tags: gap-fill
- Brand: Ojjaara / Omjjara
- Modality: Small-molecule JAK1/JAK2/ACVR1 inhibitor
- Mechanism: Inhibits JAK1/2 for spleen and symptoms and ACVR1 (ALK2) to lower hepcidin and improve anaemia.
- Approvals: US 2023: Intermediate/high-risk myelofibrosis with anaemia; EU 2024: Myelofibrosis with moderate-to-severe anaemia

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Momelotinib
- MOMENTUM (Lancet 2023): https://doi.org/10.1016/S0140-6736(22)02036-0
- Label (DailyMed): https://dailymed.nlm.nih.gov/dailymed/search.cfm?labeltype=all&query=momelotinib

## Connected records

- cancers: [Myeloproliferative neoplasms (PV, ET, myelofibrosis)](https://onco.cc/cancers/myeloproliferative-neoplasms/), [Polycythaemia vera (PV)](https://onco.cc/cancers/polycythaemia-vera/), [Primary myelofibrosis](https://onco.cc/cancers/primary-myelofibrosis/)
- technologies: [Small-molecule kinase inhibitors](https://onco.cc/technologies/kinase-inhibitors/)
- targets: [ACVR1 (ALK2)](https://onco.cc/targets/acvr1/), [JAK1](https://onco.cc/targets/jak1/), [JAK2](https://onco.cc/targets/jak2/)
- companies: [GSK](https://onco.cc/companies/gsk/)
- key papers: [COMFORT-I: ruxolitinib, the first JAK inhibitor, versus placebo for myelofibrosis](https://onco.cc/key-papers/paper-comfort-1-ruxolitinib-myelofibrosis-nejm-2012/), [MOMENTUM: momelotinib versus danazol for myelofibrosis patients with anaemia after a prior JAK inhibitor](https://onco.cc/key-papers/paper-momentum-momelotinib-lancet-2023/)
- terms: [DIPSS, DIPSS-plus and MIPSS70 (myelofibrosis risk scores)](https://onco.cc/terms/dipss-mipss70/), [Post-PV myelofibrosis (spent phase)](https://onco.cc/terms/post-pv-myelofibrosis/)
- drugs: [Danazol](https://onco.cc/drugs/danazol/)
- trials: [MOMENTUM](https://onco.cc/trials/momentum/)

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