Inrebic

Pronunciation: inn-REH-bik
Generic name: fedratinib [ fed-RA-ti-nib ]
Dosage form: capsule (100mg)
Drug class: Multikinase inhibitors

Medically reviewed by Melisa Puckey, BPharm. Last updated on Feb 22, 2024.

What is Inrebic?

Inrebic (fedratinib) capsules are used for myelofibrosis (MF) in adults to reduce the symptoms of MF, including night sweats, itching, stomach pain, feeling full when eating, pain under the ribs on the left-hand side, and bone or muscle pain.  Inrebic also helps reduce the spleen volume. Inrebic works by blocking certain types of enzymes called Janus Associated Kinase 2 (JAK2) and so is called and JAK2 inhibitor.

Myelofibrosis is a rare type of bone marrow disorder that causes extensive scarring in your bone marrow, which reduces the ability of the bone marrow to make blood cells. This leads to anemia that can cause weakness and tiredness, and MF may cause an enlarged spleen. Myelofibrosis is considered to be a chronic leukemia that can happen on its own, called primary myelofibrosis, or it can develop from another bone marrow disorder, which is called secondary myelofibrosis.

Inrebic became an FDA-approved medicine on August 16, 2019, for the treatment of adult patients with intermediate-2 or high-risk primary or secondary (post-polycythemia vera or post-essential thrombocythemia) myelofibrosis.

Inrebic side effects

Common Inrebic side effects may include nausea, vomiting, diarrhea, or anemia.

Serious Inrebic side effects

Get emergency medical help if you have signs of an allergic reaction to Inrebic: hives, difficulty breathing, swelling of your face, lips, tongue, or throat.

Some people using Inrebic have developed vitamin B1 deficiency that resulted in serious and sometimes fatal brain damage. Seek emergency medical attention if you have symptoms such as:

• drowsiness, confusion, memory problems;
• vision problems, unusual eye movements; or
• problems with coordination and muscle movement.

Call your doctor at once if you have:

• severe or ongoing nausea, vomiting, or diarrhea (even while you are taking medication to prevent these effects);
• easy bruising, unusual bleeding, purple or red spots under your skin;
• low red blood cells (anemia) - pale skin, unusual tiredness, feeling light-headed or short of breath, cold hands and feet; or
• low white blood cell counts - fever, mouth sores, skin sores, sore throat, cough, trouble breathing.

You may need a blood transfusion if your blood counts get too low.

This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Warnings

Some people using Inrebic have developed vitamin B1 deficiency that resulted in serious and sometimes fatal brain damage. Your vitamin B1 levels will need to be checked before and during treatment, and you may need to take a vitamin B1 supplement.

Get emergency medical help if you have symptoms such as drowsiness, confusion, memory problems, vision problems, unusual eye movements, or problems with coordination and muscle movement.

Driving and using machines: While using this medicine, you may feel weak, tired, dizzy, or confused. You may have blurred vision. Before driving a vehicle or using machinery, wait to see how you feel after taking Inrebic.

Call your doctor if you are sick with vomiting or diarrhea even while taking medications to prevent these side effects.

Before taking this medicine

To make sure Inrebic is safe for you, tell your doctor if you have ever had:

• low levels of platelets or red blood cells;
• liver disease;
• kidney disease; or
• if you have been taking ruxolitinib (Jakafi).

Inrebic is not for use in patients under the age of 18 years.

It is not known whether fedratinib will harm an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant.

You should not breastfeed while using Inrebic, and for at least 1 month after your last dose.

How should I take Inrebic?

Take Inrebic exactly as prescribed by your doctor. Follow all directions on your prescription label and read all medication guides or instruction sheets. Your doctor may occasionally change your dose.

You may take Inrebic capsule with or without food. Take with a high-fat meal if Inrebic upsets your stomach.

Your vitamin B1 (thiamine) levels will need to be checked before and during treatment with Inrebic. You may need to take a vitamin B1 supplement.

You may be given other medications to help prevent nausea, vomiting, and diarrhea. Keep using these medicines for as long as your doctor has prescribed.

Call your doctor if you are sick with vomiting or diarrhea even while taking medications to prevent these side effects. You can easily become malnourished from vomiting and diarrhea. This can lead to low vitamin B1 levels.

Inrebic can lower your blood cell counts and affect liver function. Your blood will need to be tested often. Your treatments may be delayed based on the results.

Do not change your dose or stop taking Inrebic without your doctor's advice.

Store at room temperature, away from moisture and heat.

Dosing information

Usual Adult Dose for Myelofibrosis:

For patients with a baseline platelet count of 50 x 109/L or greater:
400 mg orally once a day

Management of thiamine levels and Wernicke's encephalopathy (WE):

• Assess thiamine levels and nutritional status prior to starting therapy, periodically during therapy, and as indicated.
• Do not initiate this drug in patients with thiamine deficiency; replete thiamine prior to therapy initiation and during therapy if thiamine levels are low.
• If Wernicke's encephalopathy is suspected, immediately discontinue therapy and initiate parenteral thiamine treatment.
• Monitor until symptoms resolve or improve and thiamine levels normalize.

Use: For the treatment of intermediate-2 or high-risk primary or secondary (post-polycythemia vera or post-essential thrombocythemia) myelofibrosis (MF)

What happens if I miss a dose?

Skip the missed dose and use your next dose at the regular time. Do not use two doses at one time.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

What to avoid

Follow your doctor's instructions about any restrictions on food, beverages, or activity.

What other drugs will affect Inrebic?

Sometimes it is not safe to use certain medications at the same time. Some drugs can affect your blood levels of other drugs you take, which may increase side effects or make the medications less effective. 

Other drugs may interact with fedratinib, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.
Some examples of medicines that interact with Inrebic are

• Strong CYP3A4 Inhibitors: Reduce Inbrebic dose as recommended. 
• Strong and Moderate CYP3A4 Inducers: Avoid use of Inbrebic.
• CYP3A4, CYP2C19, or CYP2D6 Substrates: Dose modifications of substrates drugs may be needed. 
• OCT2 and MATE1/2-K Substrates: Dose modifications of substrate drugs may be needed.

Not all possible interactions are listed here. Click on the link below to check interactions.

Inrebic Package Insert

Review the Inrebic Package Insert for more detailed information about this medicine. Discuss any medical questions you have with your doctor or other health care provider. This is not all the information you need to know about this medicine for safe and effective use, and it does not take the place of talking to your doctor about your treatment.

Storage

Store capsules below 86°F (30°C)

Ingredients

Active Ingredient: fedratinib.

Inactive ingredients: silicified microcrystalline cellulose and sodium stearyl fumarate. The capsule shell contains gelatin, red iron oxide, titanium dioxide and white ink.

Company

Bristol-Myers Squibb Company, Princeton, NJ 08543 USA.

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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