Enasidenib is an antineoplastic agent that belongs specifically to the class of medications called IDH2 inhibitors. It is used to treat a specific type of acute myeloid leukemia (AML), that has returned or that has not responded to another treatment. It may take up to 6 months of using this medication before it starts to work.

Acute myeloid leukemia is a type of blood cancer that occurs when the bone marrow stops producing normal blood cells. Enasidenib works by blocking the action of an abnormal enzyme which causes the bone marrow to overproduce immature blood cells. Blocking this enzyme allows the numbers of normal blood cells to increase. Enasidenib has been granted a notice of compliance with conditions (NOC/c) by Health Canada. This means that Health Canada has approved this medication to be marketed based on promising evidence of effectiveness, but additional results of studies are needed to verify its effectiveness. An NOC/c is used to allow access to products that are used to treat or prevent serious, life-threatening, or severely debilitating illness.

This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.

Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.

Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.

The recommended dose of this medication is 100 mg taken by mouth, once daily. It may be taken with or without food. Do not chew, crush, or split the tablet. Swallow the tablet whole with water.

Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.

It is important to take this medication exactly as prescribed by your doctor.

If you miss a dose, or vomit after taking the dose, take it as soon as possible and continue with your regular schedule. If it is almost time for your next dose, skip the missed dose and continue with your regular dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication in its original package at room temperature, protect it from light and moisture, and keep it out of the reach of children.

Do not take this medication if you are allergic to enasidenib or any ingredients of the medication.

Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.

The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.

The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.

Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.

• changed sense of taste
• decreased appetite
• diarrhea
• fatigue
• nausea
• vomiting

Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.

Check with your doctor as soon as possible if any of the following side effects occur:

• difficulty breathing at rest or worsens when lying down
• fever
• signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
• signs of clotting problems (e.g., unusual nosebleeds, bruising, blood in urine, coughing blood, bleeding gums, cuts that don’t stop bleeding)
• signs of infection (e.g., fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
• signs of liver problems (e.g., nausea, vomiting, diarrhea, loss of appetite, weight loss, yellowing of the skin or whites of the eyes, dark urine, pale stools)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• low levels of oxygen (hypoxia; changes in skin colour, confusion, fast heart rate, rapid breathing, shortness of breath, sweating, wheezing)
• symptoms of differentiation syndrome (e.g., fever, cough, shortness of breath, arm, leg or neck swelling, fast weight gain, dizziness, lightheadedness, bone pain)
• symptoms of tumour lysis syndrome (e.g., producing less urine, cloudy urine, kidney problems, muscle spasms, nausea, shortness of breath)

Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.

Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.

Anemia: Enasidenib may cause low levels of red blood cells. If you experience symptoms of reduced red blood cell count (anemia) such as shortness of breath, feeling unusually tired, or pale skin, contact your doctor as soon as possible. Your doctor will order routine blood tests to make sure potential problems are caught early.

Bleeding: Enasidenib may cause a reduced number of platelets in the blood, which can make it difficult to stop cuts from bleeding. If you notice any signs of bleeding, such as frequent nosebleeds, unexplained bruising, or black and tarry stools, notify your doctor as soon as possible. Your doctor will order routine blood tests to make sure potential problems are caught early.

Birth control: Women of childbearing age who are taking enasidenib or whose male partners are taking enasidenib should use an effective method of birth control such as condoms during treatment and for at least 8 weeks after stopping the medication. If you become pregnant while taking this medication, contact your doctor immediately.

White blood cells: As well as preventing cancer cells from forming, enasidenib can reduce the number of cells that fight infection in the body (white blood cells). If possible, avoid contact with people with contagious infections. Tell your doctor immediately if you notice signs of an infection, such as fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness. Your doctor will do blood tests regularly to monitor the number of specific types of blood cells in your blood.

Early in treatment, enasidenib can also cause the body to produce too many white blood cells. When this happens, it is usually within 3 months of starting the medication. If you experience fever for no apparent reason, contact your doctor as soon as possible.

Differentiation syndrome: Differentiation syndrome occurs when there is a rapid overproduction of certain blood cells. This condition can be severe and even life-threatening. It may occur 10 days to 5 months after you start to take enasidenib. If you experience symptoms of differentiation syndrome, such as unexplained fever, cough, shortness of breath, swelling of the arms or legs, or swelling around the neck, groin, or underarms, rapid weight gain or fluid retention, bone pain, dizziness or lightheadedness contact your doctor as soon as possible.

Liver function: This medication may cause a decrease in liver function. If you experience symptoms of liver problems such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

Tumour lysis syndrome: Enasidenib, like many other cancer medications, causes many cancer cells to be suddenly killed when treatment is first started. This can overwhelm the body with waste products from the cells. As a result, the body may not be able to keep up with getting rid of all the waste. When this happens, you may experience nausea, shortness of breath, cloudy urine, or joint pain. This is called tumour lysis syndrome. Your doctor may prescribe some medications to help your body get rid of the waste products. Make sure you understand how to use these medications and report any of these signs or symptoms to your doctor immediately.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Breast-feeding: It is not known if enasidenib passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Women should avoid breast-feeding while taking enasidenib and for 8 weeks after the last dose of the medication.

Children: The safety and effectiveness of using this medication have not been established for children.

Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications that you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them. Depending on your specific circumstances, your doctor may want you to:

• stop taking one of the medications,
• change one of the medications to another,
• change how you are taking one or both of the medications, or
• leave everything as is.

An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.