Bavencio (avelumab) is a prescription drug used to treat certain types of kidney, bladder, and skin cancer. Bavencio can cause side effects that range from mild to serious. Examples include fatigue, skin rash, and nausea.

Specifically, Bavencio is a biologic drug used to treat the following in adults:

Bavencio can also be used in children ages 12 years and older to treat Merkel cell carcinoma.

The active ingredient in Bavencio is avelumab. The drug comes as a liquid solution given via intravenous (IV) infusion (an injection into a vein given over time). The infusion typically takes about 60 minutes to complete.

Keep reading to learn about the common, mild, and serious side effects Bavencio can cause. For a general overview of the drug, including details about its uses, see this article.

* For this indication, Bavencio is typically used along with axitinib (Inlyta).
† “Locally advanced” means the cancer has spread to nearby tissue, but not to other areas of the body. “Metastatic” means the cancer has spread to other areas of the body from where it started.

Some people may experience mild to serious side effects during Bavencio treatment. Examples of the drug’s commonly reported side effects include:

* To learn more about this side effect, see the “Side effects explained” section below.

Mild side effects have been reported with Bavencio. These include:

  • skin rash
  • diarrhea
  • cough
  • decreased appetite
  • nausea
  • muscle or bone pain
  • fatigue

In most cases, these side effects should be temporary. And some may be easily managed. But if you have symptoms that are ongoing or bothersome, talk with your doctor or pharmacist. And do not stop Bavencio treatment unless your doctor recommends it.

Bavencio may cause mild side effects other than those listed above. See the drug’s prescribing information for details.

Serious side effects have been reported with Bavencio. These include:

If you develop serious side effects during Bavencio treatment, 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.

* To learn more about this side effect, see the “Side effects explained” section below.

Note: After the Food and Drug Administration (FDA) approves a drug, it tracks and reviews side effects of the medication. If you’d like to notify the FDA about a side effect you’ve had with Bavencio, visit MedWatch.

Allergic reaction

For some people, Bavencio can cause an allergic reaction.

In general, symptoms of an allergic reaction can be mild or serious. You can learn more about possible symptoms in this article.

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. They may suggest a treatment to manage your symptoms and can determine whether you should continue receiving Bavencio.

If you have symptoms of a severe allergic reaction, such as swelling or trouble breathing, call 911 or your local emergency number right away. These symptoms could be life threatening and require immediate medical care.

If your doctor confirms you’ve had a serious allergic reaction to Bavencio, they may have you switch to a different treatment.

Get answers to some frequently asked questions about Bavencio’s side effects.

How do side effects of Bavencio compare with those of Keytruda?

Bavencio and Keytruda are both prescribed for certain types of skin, bladder, and kidney cancer. Based on Bavencio studies and Keytruda studies, both medications have similar side effects. These include fatigue, bone or muscle pain, rash, cough, and diarrhea.

These two drugs can also cause side effects other than those listed. See the Bavencio prescribing information and the Ketruda prescribing information for more details.

How does Bavencio affect the immune system?

Bavencio is a type of immunotherapy. The way it works (also called its mechanism of action) is by strengthening your immune system.

Sometimes drugs that boost your immune system will cause it to become too strong. When this occurs, your immune system can begin to attack other areas of your body, which can lead to immune system reactions.

To learn more about immune system reactions, see the “Side effects explained” section below.

Learn more about some of the side effects Bavencio may cause.

Infusion reactions

Infusion reactions are a common and serious side effect reported in studies of Bavencio. Infusion reactions may cause symptoms such as:

Factors that can increase the risk of infusion reactions when using this drug include having a history of infusion reactions.

What might help

Talk with your doctor about medications you can take before each Bavencio infusion to help decrease the risk of infusion reactions. Examples of these premedications include acetaminophen (Tylenol) and diphenhydramine (Benadryl). It’s recommended that you take these medications before your first four doses of Bavencio at the very least.

Your doctor will monitor you during each infusion for any reactions. If you have a severe or life threatening infusion reaction, your doctor will stop your Bavencio treatment and recommend a different drug.

Talk with your doctor if you have any questions or concerns about your risk of infusion reactions.

Immune system reactions

Immune system reactions are a serious side effect reported in studies of Bavencio. This drug is a type of immunotherapy that works by strengthening your immune system. Sometimes drugs that boost your immune system will cause it to become too strong. When this occurs, your immune system can begin to attack other areas of your body, which can lead to immune system reactions.

Based on the location of these reactions, your risk of certain conditions may be higher and symptoms will vary. Some of these conditions include:

Bavencio may cause immune system reactions other than those listed above. See the drug’s prescribing information for details.

What might help

Your doctor will order a blood test to check your liver, kidney, and thyroid function before you start Bavencio treatment. They’ll also be closely monitoring you for immune system reactions during treatment.

Talk with your doctor or pharmacist if you have any questions about these side effects or what symptoms to watch for.

Keeping track of side effects

During your Bavencio treatment, consider taking notes on any side effects you’re having. You can then share this information with your doctor. This is especially helpful when you first start a new drug or combination of treatments.

Your side effect notes can include things such as:

  • what dose of the drug you were receiving when you had the side effect
  • how soon you had the side effect after starting that dose
  • what your symptoms were
  • how your symptoms affected your daily activities
  • what other medications you were taking
  • any other information you feel is important

Keeping notes and sharing them with your doctor will help them learn more about how Bavencio affects you. They can then use this information to adjust your treatment plan if needed.

Below is important information you should consider before starting Bavencio.

Heart conditions

Bavencio and axitinib (Inlyta) are often used together to treat a type of kidney cancer called renal cell carcinoma. The combination of these two drugs can cause serious heart problems, including heart attack and heart failure.

Talk with your doctor about any heart conditions you may have before starting Bavencio. They may recommend a different treatment option for you. Or if you do take Bavencio, they may monitor you more closely during treatment.

Solid organ or stem cell transplant

If you’ve had a solid organ transplant or stem cell transplant, Bavencio may not be right for you. This is because Bavencio can increase your risk of transplant rejection or certain serious conditions, such as graft-versus-host disease.

If you’ve had a solid organ or stem cell transplant, talk with your doctor about the best treatment option for your condition.

Other warnings

Bavencio can sometimes cause harmful effects in people with certain conditions. This is known as a drug-condition interaction. Other factors may also affect whether Bavencio is a good treatment option for you.

Talk with your doctor about your health history before starting Bavencio. Be sure to tell them if any of the following factors apply to you:

  • immune system conditions
  • previous allergic reaction to Bavencio
  • pregnancy
  • breastfeeding

Alcohol and Bavencio

There are no known interactions between alcohol and Bavencio. However, alcohol consumption may increase your risk of liver damage and Bavencio can also cause liver damage. So consuming alcohol during Bavencio treatment can worsen liver problems or increase the risk of them.

If you have questions about consuming alcohol during Bavencio treatment, talk with your doctor or pharmacist.

Pregnancy and breastfeeding with Bavencio

Before starting Bavencio treatment, it’s important to talk with your doctor if you’re pregnant, breastfeeding, or planning to become pregnant or breastfeed.

Pregnancy

Studies are not available on the use of Bavencio during pregnancy. But based on how the drug works, Bavencio may cause harm to a fetus when taken by someone who is pregnant.

If you’re pregnant or planning to become pregnant, talk with your doctor about your treatment options.

If you’re able to become pregnant, your doctor may recommend using birth control during Bavencio treatment and for at least 1 month after it’s finished.

Breastfeeding

There aren’t any studies on whether Bavencio passes into breast milk, but it could cause serious side effects in a child who is breastfed. You should not breastfeed during Bavencio treatment and for at least 1 month after your last dose.

If you’re breastfeeding or planning to do so, talk with your doctor about your options.

Disclaimer: Healthline 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.