If you have a certain kind of cancer, your doctor might suggest Libtayo as a treatment option for you.

Some forms of the following cancers are treated with libtayo.

You will likely receive libtayo until your cancer gets worse or you have side effects.

Libtayo is a biologic, which is a drug that’s made from parts of living organisms. The active ingredient in Libtayo is cemiplimab-rwlc. An active ingredient is what makes a drug work.

This drug comes as a solution that a healthcare professional gives as an intravenous (IV) infusion. This is an injection of medication into a vein given over a period of time.

For more information about Libtayo, including details about its uses, see this in-depth article on the drug.

Mild to serious side effects can be caused by the drug. Continue reading to learn more.

Some people may experience side effects during their treatment. Some of the reported side effects of Libtayo are listed.

There are a few side effects that may be caused by libtayo. There are additional side effects of Libtayo listed.

Mild side effects can be caused by the medication.

Mild side effects have been reported with the program.

The side effects explained section is where you can learn more about this side effect.

“These side effects should be temporary. Some may be easy to manage. If you have any symptoms that bother you, talk to your doctor or pharmacist. Unless your doctor recommends it, don’t stop using libtayo.”

Libtayo may cause mild side effects other than the ones listed above. See the Libtayo prescribing information for details.

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

It may cause serious side effects.

There have been serious side effects reported with Libtayo.

The side effects explained section is where you can learn more about this side effect.

If you develop serious side effects, you should call your doctor. If the side effects seem life threatening or you think you have a medical emergency, immediately call the emergency number.

Some of the side effects of libtayo may be discussed.

Infusion reactions

You’ll receive Libtayo as an intravenous (IV) infusion (an injection of medication into a vein given over time). As a result, you may have infusion reactions from treatment with this drug. These are reactions that occur during or immediately after receiving a Libtayo IV infusion.

Serious infusion reactions were very rare in studies of Libtayo, but may still happen.

The most common reactions reported in these studies are:

Other reactions are possible.

What might help

A healthcare professional will be watching you. If you have symptoms of an infused reaction, they will likely slow down or stop the infused reaction. They may recommend treatment for your symptoms.

If your reaction is severe, a healthcare professional will recommend you stop treatment.

Immune reactions

Libtayo treats cancer by increasing activity in your immune system. But in rare cases, this can cause your immune system to attack parts of your body by mistake. This is known as an immune reaction (also called immune-mediated reaction).

These reactions were rare in studies of Libtayo. But in extreme cases, they may lead to hospitalization or even be fatal.

There are different symptoms of an immune reaction. The symptoms vary depending on which part of your body is affected.

Immune reactions caused by libtayo can affect your body. It is possible to have more than one immune reaction at the same time.

These reactions can happen at any time during your treatment. It is possible for them to occur even after your last dose of the drug.

The table below lists examples of immune reactions and symptoms reported in studies of Libtayo.

Libtayo immune reaction Possible symptoms
colitis • belly pain
bloody stool
• loose or more frequent bowel movements
hepatitis yellowing of your skin or the whites of your eyes
• Nausea and vomiting.
• pain on the right side of your belly
nephritis bloody urine
making less urine than usual
• swelling in your ankles or lower legs
pneumonitis chest pain
• cough
• trouble breathing
thyroiditis • behavior or mood changes
feeling cold
hair loss
• weight changes

What might help

If you notice symptoms of an immune reaction, contact your doctor. Depending on the severity of your symptoms, they will either stop or pause the treatments.

To help lessen symptoms, your doctor may also prescribe treatments such as a corticosteroid. An example of this type of drug is prednisone.

Blood disorders

Blood disorders are possible with Libtayo treatment. Though rare, serious cases were reported in studies of Libtayo. These include:

Unless they become serious, these blood disorders may not cause symptoms. Mild blood disorders are only detected through lab tests.

What might help

Your doctor will have you get blood tests during your treatment. These tests will check the blood levels of various substances to see if they are high or low.

Depending on the results, your doctor may prescribe treatment to correct the levels of substances. They may temporarily stop your treatment.

Urinary tract infection

It’s possible to have a urinary tract infection (UTI) as a side effect of Libtayo.

These infections weren’t common in studies of Libtayo. But they can be serious in rare cases.

Mild UTI symptoms can include:

A more serious UTI may include symptoms.

  • There is a high degree of fever. or “It’s cold.”
  • There is pain in your back and sides.
  • Nausea and vomiting.

What might help

If you notice symptoms of a UTI while you’re receiving Libtayo, contact your doctor right away. They’ll likely want to test your urine for infection. This test also helps them determine the best treatment for your UTI.

Your doctor will recommend whether or not you should continue receiving libtayo.

Allergic reaction

Like most drugs, Libtayo can cause an allergic reaction in some people. This side effect was rare in studies of Libtayo.

Mild to serious symptoms can be present.

What might help

If you have mild symptoms of an allergic reaction, such as a mild rash, call your doctor right away. To manage symptoms, they may suggest an over-the-counter antihistamine you take by mouth, such as Benadryl (diphenhydramine). Or they may recommend a product you apply to your skin, such as hydrocortisone cream.

If your doctor confirms you had an allergic reaction to libtayo, they will decide if you should continue using it.

If you have a severe allergic reaction, you should call the emergency number. These symptoms could be life threatening and need immediate medical care.

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

Keeping track of side effects

Keep notes on any side effects you are having during your treatment. You can share this information with your doctor. This is helpful when you are starting to use a combination of treatments.

Side effect notes can include things.

  • What dose of drug did you take when you had the side effect?
  • How soon did you experience the side effect?
  • What are your symptoms?
  • How did it affect your daily activities?
  • What other drugs were you taking?
  • Other information is important to you.

Sharing your notes with your doctor will help them learn more about how libtayo affects you. If needed, they can use this information to adjust your treatment plan.

If you have a medical condition that affects your health, libtayo may not be right for you. Before starting libtayo, you should talk to your doctor about your health history. The list has factors to consider.

Autoimmune conditions. Libtayo can cause immune system problems. If you have an autoimmune condition, such as lupus, you may have a higher risk of this Libtayo side effect. Your condition may also worsen from using this drug. Before you start Libtayo treatment, tell your doctor about any autoimmune conditions you have. This will help them determine whether Libtayo is safe for you.

Organ or stem cell transplant. If you’ve had an organ transplant or certain kind of stem cell transplant, taking Libtayo may result in serious side effects. For example, Libtayo may cause your body to reject an organ transplant. If you’ve had either type of transplant, your doctor will likely not prescribe Libtayo. They’ll discuss safer treatment options with you instead.

Nervous system conditions. Treatment with Libtayo can result in immune system problems. This may worsen existing nervous system conditions, such as myasthenia gravis. Tell your doctor about any nervous system conditions you have. They can discuss with you whether Libtayo is a safe treatment option.

Allergic reaction. If you’ve had an allergic reaction to Libtayo or any of its ingredients, your doctor will likely not prescribe Libtayo. Ask them what other medications are better options for you.

Alcohol and Libtayo

There’s no known interaction between using Libtayo and drinking alcohol.

Alcohol could increase the risk of certain side effects.

  • fatigue (low energy)
  • There is a lot of There is a lot of There is a lot of diarrhea…
  • nausea

If you drink alcohol, talk to your doctor about how much you should consume.

Pregnancy and breastfeeding while receiving Libtayo

It is not safe to use libtayo during pregnancies or breastfeeding.

If you can become pregnant, your doctor will give you a pregnancy test before prescribing Libtayo. They’ll also recommend you use effective birth control while receiving the drug and for at least 4 months after your last dose.

You should avoid breastfeeding for at least 4 months after your last dose of libtayo, as recommended by your doctor.

Some serious side effects can be caused by the drug, like Libtayo.

If you want to learn more about the side effects of libtayo, you should talk to your doctor or pharmacist. You need to ask questions to get the answers you need. Some examples to consider.

  • Is there a way to lower my risk of side effects from libtayo?
  • Do other drugs increase my risk of side effects with libtayo?
  • How do the side effects of libtayo compare to other treatments?


Will my hair fall out?



It’s very unlikely. Hair loss wasn’t a side effect reported in studies of Libtayo.

Hair loss can be a symptom of a problem with the hormones. In rare cases, the immune system can be affected by the hormones. Your immune system attacks parts of your body. These reactions are different from allergic reactions. Immune reactions can cause hair loss.

If you notice hair loss, you should contact your doctor. This may be a sign of a problem with the hormones. If your doctor confirms you have an immune reaction to libtayo, they will likely stop your treatment.

The Healthline Pharmacist TeamAnswers represent the opinions of our medical experts. All content is strictly informational and should not be considered medical advice.

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.