Last reviewed 2026-04-20 · How we verify

Inrebic (FEDRATINIB HYDROCHLORIDE)

Fedratinib inhibits JAK2 and FLT3 kinases, reducing STAT3/5 phosphorylation and cell proliferation in MPNs.

Inrebic (fedratinib hydrochloride) is a small molecule modality developed by IMPACT and currently owned by Bristol-Myers. It targets cyclin-G-associated kinase, a protein involved in the proliferation and survival of cancer cells. Inrebic is FDA-approved for the treatment of myelofibrosis, a type of bone marrow disorder, and has a half-life of 41 hours. The commercial status of Inrebic is patented, with no generic manufacturers available. Key safety considerations include the risk of serious side effects such as posterior reversible encephalopathy syndrome (PRES) and pancreatitis.

At a glance

Mechanism of action

Fedratinib is a kinase inhibitor that targets JAK2 and FLT3. By blocking these kinases, it reduces the abnormal cell growth seen in myeloproliferative neoplasms like myelofibrosis. It does this by stopping the activation of STAT3/5 proteins, which are key in promoting cell division and survival.

Approved indications

• Myelofibrosis
• Post-essential thrombocythaemia myelofibrosis
• Post-polycythaemia vera myelofibrosis
• Primary myelofibrosis

Boxed warnings

• WARNING: ENCEPHALOPATHY INCLUDING WERNICKE'S Serious and fatal encephalopathy, including Wernicke's, has occurred in patients treated with INREBIC. Wernicke's encephalopathy is a neurologic emergency. Assess thiamine levels in all patients prior to starting INREBIC. Do not start INREBIC in patients with thiamine deficiency; replete thiamine prior to treatment initiation. While on treatment all patients should receive prophylaxis with daily oral thiamine and should have thiamine levels assessed as clinically indicated. If encephalopathy is suspected, immediately discontinue INREBIC and initiate parenteral thiamine. Monitor until symptoms resolve or improve and thiamine levels normalize [see Dosage and Administration (2.6) , Warnings and Precautions (5.1) and Adverse Reactions (6.1) ] . WARNING: ENCEPHALOPATHY INCLUDING WERNICKE'S See full prescribing information for complete boxed warning. Serious and fatal encephalopathy, including Wernicke's, has occurred in patients treated with INREBIC. Wernicke's encephalopathy is a neurologic emergency. Assess thiamine levels in all patients prior to starting INREBIC. Do not start INREBIC in patients with thiamine deficiency; replete thiamine prior to treatment initiation. While on treatment all patients should receive prophylaxis with daily oral thiamine and should have thiamine levels assessed as clinically indicated. If encephalopathy is suspected, immediately discontinue INREBIC and initiate parenteral thiamine. Monitor until symptoms resolve or improve and thiamine levels normalize. ( 2.6 , 5.1 , 6.1 ).

Common side effects

• Diarrhea
• Nausea
• Anemia
• Vomiting
• Fatigue
• Thrombocytopenia
• Constipation
• Cardiac failure
• Muscle spasms
• Blood creatinine increased
• Pain in extremity
• Alanine aminotransferase Increased

Key clinical trials

• Phase III Study of SAR302503 in Intermediate-2 and High Risk Patients With Myelofibrosis (PHASE3)

Patents

Primary sources

Every claim on this page is sourced from regulatory or scientific primary sources. See our editorial policy for full methodology.

Competitive intelligence

For the full competitive landscape — auto-detected comparators, recent regulatory actions across the set, upcoming PDUFA, patent timeline, sponsor landscape:

• Inrebic CI brief — competitive landscape report
• Inrebic updates RSS · CI watch RSS
• Bristol-Myers Squibb portfolio CI