Libtayo (cemiplimab-rwlc) is a brand-name prescription medication. It’s approved by the Food and Drug Administration (FDA) to treat certain types of lung cancer and skin cancer. Libtayo may be used in some situations for adults with:

Here are some fast facts about Libtayo:

  • Active ingredient: cemiplimab-rwlc, which is a biologic
  • Drug class: programmed death receptor-1 (PD-1) blocker
  • How it’s given: IV infusion by a healthcare professional
  • FDA approval year: 2018

If Libtayo works for you, your doctor will likely recommend that you take it long term.

Like other drugs, Libtayo can cause adverse effects (side effects). Read on to learn about potential common, mild, and serious side effects. For a general overview of Libtayo, including details about its uses, see this article.

* For this use, Libtayo received accelerated approval from the FDA. Accelerated approval is based on the results of early clinical trials of the medication. The FDA will decide on full approval of Libtayo for this use after more trials have been completed.

Libtayo 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. If the side effects last longer than that, bother you, or become severe, be sure to talk with your doctor or pharmacist.

These are just a few of the more common side effects reported by people who received Libtayo in clinical trials:

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

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

Mild side effects that have been reported with Libtayo include:

These side effects may be temporary, lasting a few days to weeks. 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 during Libtayo treatment and want to tell the FDA about it, visit MedWatch.

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

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

If you develop serious side effects during Libtayo 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.

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

* For more information about this side effect, see “Side effect specifics” below.
† An allergic reaction is possible after using Libtayo. However, it’s not clear whether this side effect occurred in clinical trials.

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

Does Libtayo cause any long-term side effects?

It’s possible for Libtayo to cause long-term side effects. However, most side effects reported by people who received Libtayo were mild or short term.

Some examples of long-term side effects that can occur during treatment with Libtayo include:

If you’re concerned about long-term side effects occurring during your treatment with Libtayo, talk with your doctor. They can give you information on what symptoms to watch for and recommend possible treatments.

* For more information, see “Serious side effects” above.

Should I expect hair loss with Libtayo?

Hair loss was not a side effect reported in clinical trials of people who received Libtayo.

However, some side effects of Libtayo may lead to hair loss. For example, the drug can cause hormone gland problems, such as thyroid disorders. In some cases, these disorders may result in hair loss.

Other cancer treatments, such as chemotherapy drugs, may also cause hair loss.

If you experience hair loss during your treatment with Libtayo, talk with your doctor. They can help determine the cause. Your doctor may also be able to recommend ways to decrease hair loss, such as using minoxidil (Rogaine).

Will Libtayo affect my immune system?

Yes, Libtayo will affect how your immune system works to treat your cancer. The medication allows your immune system to identify cancer cells and kill them.

Libtayo does this by strengthening your immune system to help it fight cancer cells. In rare cases, Libtayo can cause your immune system to mistakenly attack your organs or other areas of your body. This is known as an immune-mediated reaction. For details, see “Serious side effects” above.

If you’re concerned about how Libtayo may affect your immune system during your treatment, talk with your doctor.

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

Bone or muscle pain

Bone and muscle pain were common side effects in people given Libtayo in clinical trials. People who received Libtayo reported:

  • joint pain
  • back, spine, or neck pain
  • pain in the arms or legs
  • muscle stiffness

Some people said that their bone or muscle pain was mild and manageable. However, other people experienced more severe bone or muscle pain.

What you can do

If you experience symptoms of bone or muscle pain with Libtayo, talk with your doctor. In rare cases, the pain may be caused by a more serious condition, such as an immune-mediated reaction.* Your doctor will likely want to evaluate you to help determine the cause of your bone or muscle pain.

Your doctor may also recommend a treatment for your pain. This could include taking an over-the-counter oral pain medication, such as acetaminophen (Tylenol) or ibuprofen (Advil). Your doctor may also suggest pain gels or creams, or physical therapy to help ease your discomfort.

* For more information, see “Serious side effects” above.

Infusion reaction

Infusion reactions may occur with Libtayo. The drug comes as a solution that your doctor or another healthcare professional gives as an IV infusion. An infusion is an injection into a vein over time. An infusion reaction is a side effect that you may experience during your infusion.

Infusion reactions were not commonly reported by people who received Libtayo. However, you should still be aware of what could occur during an infusion. In clinical trials, people given Libtayo reported symptoms such as:

Serious infusion reactions were not common in trials of people who received Libtayo.

What you can do

Because you’ll receive your Libtayo infusions in a hospital or other healthcare facility, a healthcare professional will likely be close by. Be sure to tell them right away if you notice any symptoms of an infusion reaction.

In some cases, they may slow down your infusion to see if your infusion reaction symptoms ease. If you have a more serious infusion reaction, they may pause or stop the infusion and treat your symptoms.

If you have concerns about possible infusion reactions with Libtayo, talk with your doctor.

High blood pressure

An increase in blood pressure may occur during treatment with Libtayo. This was not a common side effect reported by people who received the medication. However, if you already have high blood pressure, Libtayo may increase your blood pressure further.

High blood pressure typically doesn’t cause any symptoms. However, if it becomes very high, you may experience:

In Libtayo clinical trials, some people experienced severely high blood pressure. However, this was rare.

What you can do

If you notice any symptoms of high blood pressure during treatment with Libtayo, check your blood pressure and let your doctor know if it’s increased. If you’re unable to measure your blood pressure, talk with your doctor. They’ll be able to check it for you.

If you monitor your blood pressure during your treatment with Libtayo and see that it has risen, be sure to talk with your doctor. As mentioned above, high blood pressure usually does not have symptoms.

If you develop high blood pressure with Libtayo, your doctor may recommend that you take a blood pressure medication. This should help manage your blood pressure during your treatment.

Diarrhea

Diarrhea was one of the most common side effects of people given Libtayo in clinical trials. In some cases, the diarrhea was severe.

It’s also possible for diarrhea to be a symptom of a more serious side effect. Examples include colitis (inflammation of the colon lining), which can happen with an immune-mediated reaction.*

Symptoms of diarrhea can include watery stool, bloating, and abdominal pain.

* For more information about immune-mediated reactions, see “Serious side effects” above.

What you can do

Be sure to tell your doctor if you experience diarrhea with Libtayo. They can help determine what may be causing it and the best way to treat it.

Your doctor will likely advise you to stay hydrated, especially if you have diarrhea often. Diarrhea can cause you to become dehydrated. Drinking water or electrolyte replacement drinks may help prevent dehydration. (Electrolytes are chemicals that help keep your body hydrated.)

In addition, your doctor may be able to recommend a medication to help ease diarrhea, such as loperamide (Imodium).

Allergic reaction

As with most drugs, Libtayo can cause an allergic reaction in some people. However, it’s not clear whether this side effect occurred in clinical trials.

Symptoms can be mild or serious and can include:

  • skin rash
  • itching
  • flushing
  • swelling under your skin, typically in your lips, eyelids, feet, or hands
  • 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 continue Libtayo treatment. If your symptoms are serious and you think you’re having a medical emergency, immediately call 911 or your local emergency number.

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

Stem cell transplant. If you receive Libtayo and had or will be having a stem cell transplant using donor stem cells, you may be at an increased risk of rejection, which can be life threatening. So, it’s important to tell your doctor if you notice any symptoms, such as nausea, vomiting, or skin rash. Your doctor will also likely monitor you frequently for symptoms of stem cell rejection. If you develop any symptoms, they may recommend a treatment option other than Libtayo.

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

Immune system conditions. Libtayo affects your immune system. If you have a condition that affects your immune system (such as Crohn’s disease, ulcerative colitis, or lupus), Libtayo may worsen it. Your doctor may monitor your symptoms more often than usual or prescribe a different treatment option.

Organ transplant. If you had an organ transplant before starting treatment with Libtayo, you might be at an increased risk of organ rejection. Your doctor will likely monitor you for symptoms of organ rejection during your treatment with Libtayo. For example, a fever may signal an infection. In some cases, they may recommend a medication other than Libtayo.

Nervous system conditions. It’s possible for Libtayo to increase your risk of developing a nervous system condition. If you already have a condition such as myasthenia gravis or Guillain-Barré syndrome, Libtayo may make your symptoms worse. Before starting treatment with Libtayo, tell your doctor if you have a nervous system condition. They may monitor you more often for worsening symptoms or recommend a treatment other than Libtayo.

Alcohol and Libtayo

Libtayo is not known to interact with alcohol. However, some of the drug’s side effects may worsen if you drink alcohol. For example, headache and nausea may occur with both alcohol and Libtayo. Consuming alcohol during Libtayo treatment may make these side effects more severe.

In addition, alcohol can increase your risk of developing liver problems. Libtayo can also cause liver problems, such as hepatitis. If you drink alcohol and receive Libtayo, your risk of liver problems may increase further.

If you’re interested in drinking alcohol during Libtayo treatment, talk with your doctor. They can advise you on how much alcohol if any, may be safe for you.

Pregnancy and breastfeeding during Libtayo treatment

Libtayo is not safe to use during pregnancy or while breastfeeding. There have not been clinical trials in pregnant people to determine the risks of this medication during pregnancy. However, in animal studies, Libtayo caused pregnancy loss.

If you can become pregnant, your doctor will likely order a pregnancy test before you first receive Libtayo. This is to confirm that you’re not pregnant. During your treatment and for at least 4 months after your last dose of Libtayo, use an effective form of birth control. If you become pregnant during your treatment with Libtayo, be sure to tell your doctor right away.

At this time, it’s unknown whether Libtayo passes into breast milk or what effects the drug may have on a breastfed child. Due to the possible risks, your doctor will likely recommend that you do not breastfeed while you’re receiving Libtayo. They’ll also probably advise you to avoid breastfeeding for at least 4 months after your last dose of the medication.

If you’re pregnant or planning to be, talk with your doctor. You should also talk with them if you’re breastfeeding or considering it. Your doctor can suggest medication other than Libtayo.

You may experience mild side effects with Libtayo. Serious side effects may also occur, but they’re rare. Be sure to talk with your doctor if you develop any serious side effects.

You can also talk with your doctor or pharmacist if you’d like to learn more about Libtayo. 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:

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.