Mylotarg (gemtuzumab/ozogamicin) is a brand-name prescription medication. It’s approved by the Food and Drug Administration (FDA) to treat certain types of acute myeloid leukemia (AML)* in adults and some children.

Here are some fast facts about Mylotarg:

As with other drugs, Mylotarg can cause side effects. Read on to learn about potential common, mild, and serious side effects. For a general overview of Mylotarg, including details about its uses and drug class, see this article.

* Mylotarg is approved to treat AML that’s relapsed (returned after a past decrease in symptoms) or refractory (hasn’t responded to past treatment).

Mylotarg can cause certain side effects, some of which are more common than others. These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are a few of the more common side effects reported by people who took Mylotarg in clinical trials:

* For more information about this side effect, see “Side effect specifics” below.

Mild side effects can occur with Mylotarg. This list doesn’t include all possible mild side effects of the drug. For more information, you can refer to Mylotarg’s prescribing information.

Mild side effects that have been reported with Mylotarg include:

These side effects may be temporary, lasting a few days to weeks. However, if the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks side effects of the medication. If you develop a side effect with Mylotarg and want to tell the FDA about it, visit MedWatch.

Mylotarg may cause serious side effects. The list below may not include all possible serious side effects of the drug. For more information, you can refer to Mylotarg’s prescribing information.

If you develop serious side effects while receiving Mylotarg, call your doctor right away. If the side effects seem life threatening or you think you’re having a medical emergency, immediately call 911 or your local emergency number.

Serious side effects that have been reported and their symptoms include:

  • Long QT syndrome (a type of irregular heart rhythm, also called QT prolongation). Symptoms can include:
    • fainting
    • dizziness
    • a “fluttering” feeling in your chest
  • Infection, including pneumonia. An infection may become severe and cause sepsis (a severe immune system response). Symptoms can include:
    • fever
    • cough
    • diarrhea
    • sore throat
    • fatigue
    • shivering
  • Febrile neutropenia (a condition that causes low white blood cell levels and a fever). Symptoms can include:
    • a temperature of 100.4°F (38°C) or higher that lasts for more than 1 hour
    • a single temperature reading of 101°F (38.3°C) or higher
  • Increased heart rate.
  • Fluid buildup in the lungs. Symptoms can include:
    • trouble breathing
    • cough
    • sweating
  • Severe bleeding.*
  • Severe liver problems.†*
  • Allergic reaction.*
  • Infusion reaction.*

* For more information about this side effect, see “Side effect specifics” below.
† Mylotarg has a boxed warning for this side effect. This is the most serious warning from the Food and Drug Administration (FDA). To learn more, see the “Side effect specifics” section below.

Mylotarg may cause several side effects. Here are some frequently asked questions about the drug’s side effects and their answers.

Does Mylotarg cause long-term side effects?

Mylotarg is not known to cause long-term side effects. Some side effects, such as infections or liver problems, may require treatment after you stop receiving Mylotarg. Most side effects should resolve with correct treatment and pausing or stopping Mylotarg treatment.

Talk with your doctor or pharmacist if you are concerned about potential long-term side effects of Mylotarg.

Can you take Mylotarg if you are pregnant or plan on becoming pregnant?

This isn’t recommended. Mylotarg can cause harm to a fetus if received during pregnancy. Due to this risk, your doctor will not prescribe Mylotarg if you are pregnant or plan on becoming pregnant. You can talk with your doctor about the best birth control method for you if you are receiving Mylotarg treatment.

See “Pregnancy and breastfeeding while taking Mylotarg” in the “Precautions for Mylotarg” section below for details.

Does Mylotarg cause immunogenicity?

Mylotarg could potentially cause immunogenicity because of how the drug works. Immunogenicity occurs if your body has an immune response to a foreign substance, such as a drug.

Immunogenicity was not studied in clinical trials of Mylotarg. Talk with your doctor or pharmacist if you are concerned about immunogenicity while receiving Mylotarg.

Learn more about some of the side effects that Mylotarg may cause. To find out more about how often side effects occurred in clinical trials, you can see the prescribing information for Mylotarg.

Bleeding

Bleeding was a common side effect in clinical trials of Mylotarg. This can occur due to prolonged low platelet levels. Mild bleeding can cause symptoms such as:

  • bruising easily
  • nose bleeds
  • bleeding from the gums
  • bleeding for a long time from minor cuts

Bleeding caused by Mylotarg can also be serious. Bleeding in the brain can occur. Rarely, some cases of bleeding in the brain in clinical trials were fatal. Due to this risk, your doctor will monitor your blood cell levels frequently during your treatment with Mylotarg.

If you develop bleeding while receiving Mylotarg, your doctor may pause or discontinue your treatment.

What you can do

Be sure to get lab tests as recommended by your doctor while you’re receiving Mylotarg. Tell them right away if you experience any symptoms of bleeding while receiving Mylotarg. You can talk with your doctor or pharmacist if you are concerned about bleeding with Mylotarg.

Infusion reactions

Infusion reactions have been reported in clinical trials of Mylotarg. An infusion reaction may occur during or up to 24 hours after a Mylotarg infusion. Symptoms may include:

  • chills
  • fever
  • low blood pressure
  • increased heart rate
  • trouble breathing

Reactions can be life threatening in some cases.

Your doctor or another healthcare professional will monitor you during and after each infusion. And you’ll be given medication before Mylotarg infusions to lower the risk of a reaction. If a reaction occurs during an infusion, the infusion will be stopped and you’ll be given medication as needed, such as antihistamines or corticosteroids.

What you can do

Call your doctor right away if you have any symptoms of an infusion reaction. Call 911 or your local emergency number if your symptoms feel life threatening. Talk with your doctor or pharmacist if you have any questions about infusion reactions while receiving Mylotarg.

Severe liver problems

Mylotarg has a boxed warning for a risk of liver problems, which can be severe or life threatening. A boxed warning is the most serious warning from the Food and Drug Administration (FDA).

Some people have developed a condition called veno-occlusive liver disease (VOD) when receiving Mylotarg. This condition is also called sinusoidal obstruction syndrome. With VOD, small blood vessels in your liver become blocked. Symptoms may include:

  • ascites (fluid buildup in your abdomen that causes swelling)
  • swelling of your liver, which can cause pain in the upper right side of your abdomen
  • rapid weight gain

This condition can also cause increased liver enzymes or increased bilirubin. Your doctor will monitor for this with blood tests during your treatment.

VOD was a common side effect in clinical trials with Mylotarg. It has occurred in people receiving Mylotarg alone or in combination with chemotherapy.

VOD was more common in people who:

Due to this risk, if you develop liver problems while receiving Mylotarg, your doctor may need to pause or discontinue your treatment.

What you can do

Tell your doctor if you have had any past liver problems. Also, tell your doctor right away if you experience any symptoms of VOD. You can talk with your doctor or pharmacist if you are concerned about liver problems during Mylotarg treatment.

Allergic reaction

As with most drugs, Mylotarg can cause an allergic reaction in some people. Allergic reactions, including anaphylaxis (a life threatening type of allergic reaction), were reported in clinical trials with Mylotarg. Infusion reactions can also be a type of allergic reaction, and are discussed just above.

Symptoms can be mild or serious and can include:

  • skin rash
  • itching
  • flushing
  • swelling under your skin, typically in your eyelids, lips, hands, or feet
  • swelling of your mouth, tongue, or throat, which can make it hard to breathe

What you can do

For mild symptoms of an allergic reaction, call your doctor right away. They may recommend ways to ease your symptoms and determine whether you should keep receiving Mylotarg. However, if your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

There are a few factors for you and your doctor to consider before you start Mylotarg treatment. These are described below.

Boxed warning: Severe liver problems

Mylotarg has a boxed warning for a risk of liver problems, which can be severe or life threatening. This is a serious warning from the Food and Drug Administration (FDA). For details, see the “Side effect specifics” section above.

Other precautions

Be sure to talk with your doctor about your health history before you receive Mylotarg. This drug may not be the right treatment option for you if you have certain medical conditions or other factors that affect your health. The conditions and factors to consider include:

Pregnancy. Mylotarg may cause harm to a fetus if the drug is given during pregnancy. Your doctor likely won’t prescribe this drug if you’re pregnant or planning to become pregnant. See “Pregnancy and breastfeeding while taking Mylotarg” just below for details.

Allergic reaction or infusion reaction. If you’ve had an allergic reaction to Mylotarg or any of its ingredients, your doctor will likely not prescribe Mylotarg. Also, tell your doctor if you have had an infusion reaction to any medications. Mylotarg can cause infusion reactions that can sometimes be life threatening. Ask your doctor what other medications may be better options for you.

History of bleeding. Bleeding is a common side effect of Mylotarg. If you have a history of bleeding or low platelet counts while taking medications, your doctor may recommend a cancer treatment other than Mylotarg.

Alcohol with Mylotarg

Mylotarg isn’t known to interact with alcohol. However, some side effects of Mylotarg, such as headache, nausea, vomiting, or liver problems, could be worsened by alcohol. If you drink alcohol, talk with your doctor about how much alcohol may be safe to drink during Mylotarg treatment.

Pregnancy and breastfeeding while taking Mylotarg

Mylotarg is not safe to receive during pregnancy or while breastfeeding. Due to how the drug works and as shown in animal studies, Mylotarg may cause harm to a fetus.

If you’re able to become pregnant, you should use birth control during Mylotarg treatment and for 6 months after your last dose. And if you’re a male* whose sexual partner could become pregnant, you should use birth control during and for 3 months after treatment with Mylotarg.

* Sex and gender exist on spectrums. Use of the term “male” in this article refers to sex assigned at birth.

Mylotarg treatment may cause mild or serious side effects. Some side effects are more common than others. For more information, see “More common side effects” above. Mylotarg may cause serious side effects in rare cases. Talk with your doctor if you develop side effects that are serious.

If you’d like to learn more about Mylotarg, talk with your doctor or pharmacist. They can help answer any questions you have about side effects of the drug.

Besides talking with your doctor, you can do some research on your own. These articles might help:

  • More information about Mylotarg. For details about other aspects of Mylotarg, refer to this article.
  • A look at acute myeloid leukemia. For details about this condition, see our cancer hub as well as these related articles.

Disclaimer: Medical News Today has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or another healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.