# Fedratinib

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

## TL;DR

A second JAK inhibitor for myelofibrosis that works after ruxolitinib fails; it carries a boxed warning for a rare brain toxicity (Wernicke encephalopathy) so thiamine is checked.

## Summary

Fedratinib is a selective JAK2 inhibitor, with additional FLT3 and BRD4 activity, that reduces JAK-STAT signalling to shrink the spleen and ease symptoms in myelofibrosis. In JAKARTA (first line) and JAKARTA-2 (after ruxolitinib) about 35 to 45% of patients achieved a spleen response, giving it evidence in ruxolitinib failure. Development was halted in 2013 after cases of encephalopathy and resumed after review; it was approved in the US in 2019 for intermediate-2 or high-risk primary or secondary myelofibrosis and in the EU in 2021, with a boxed warning for Wernicke encephalopathy, so thiamine is checked before and during treatment. Anaemia and thrombocytopenia occur as with other JAK inhibitors. For a newcomer: a myelofibrosis pill that works after ruxolitinib, with a rare brain toxicity that vitamin monitoring prevents.

## Fields

- Kind: Treatment
- Status: approved
- Last checked: 2026-09-08
- Tags: gap-fill
- Brand: Inrebic
- Modality: Small-molecule JAK2/FLT3 inhibitor
- Mechanism: Selective JAK2 inhibitor (also FLT3, BRD4) reducing JAK-STAT signalling and splenomegaly.
- Approvals: US 2019: Intermediate-2/high-risk primary or secondary myelofibrosis; EU 2021: Myelofibrosis, JAK-inhibitor-naive or after ruxolitinib

## Sources

- Wikipedia: https://en.wikipedia.org/wiki/Fedratinib
- Label (DailyMed): https://dailymed.nlm.nih.gov/dailymed/search.cfm?labeltype=all&query=fedratinib

## Connected records

- cancers: [Myeloproliferative neoplasms (PV, ET, myelofibrosis)](https://onco.cc/cancers/myeloproliferative-neoplasms/), [Primary myelofibrosis](https://onco.cc/cancers/primary-myelofibrosis/)
- technologies: [Small-molecule kinase inhibitors](https://onco.cc/technologies/kinase-inhibitors/)
- targets: [BRD4](https://onco.cc/targets/brd4/), [FLT3](https://onco.cc/targets/flt3/), [JAK2](https://onco.cc/targets/jak2/)
- companies: [Bristol Myers Squibb](https://onco.cc/companies/bms/)
- trials: [A Study to Assess the Safety and Tolerability of BMS-986158 Alone and in Combination With Either Ruxolitinib or Fedratinib in Participants With Blood Cancer (Myelofibrosis)](https://onco.cc/trials/nct04817007/)
- 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/)
- terms: [DIPSS, DIPSS-plus and MIPSS70 (myelofibrosis risk scores)](https://onco.cc/terms/dipss-mipss70/)

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