Pemazyre (pemigatinib) is a brand-name oral tablet that’s prescribed for bile duct cancer or a certain type of blood cancer in adults. As with other drugs, Pemazyre can cause side effects, such as hair loss.

Pemazyre 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 just a few of the more common side effects reported by people who took Pemazyre in clinical trials:

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

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

Mild side effects that have been reported with Pemazyre 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 and reviews side effects of the medication. If you develop a side effect while taking Pemazyre and want to tell the FDA about it, visit MedWatch.

* For more information about this side effect, see “Side effect specifics” below.
† An allergic reaction is possible after using Pemazyre. However, this side effect wasn’t reported in clinical trials. To learn more, see the “Side effect specifics” section below.

Pemazyre 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 Pemazyre’s prescribing information.

If you develop serious side effects while taking Pemazyre, 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:

  • Acute kidney injury (your kidneys stop working properly). This can happen suddenly or over a few days. Symptoms may include:
    • feeling weak or tired
    • urinating less than normal
    • confusion
    • swelling in the legs, ankles, or feet
    • shortness of breath
    • chest pain or pressure
  • An eye problem called retinal pigment epithelial detachment (a condition where fluid enters into a layer of cells under your retina). Symptoms can include:
  • Hyperphosphatemia (too much phosphate in your blood).*
  • Severe allergic reaction.†

* For more information about this side effect, see “Side effect specifics” below.
† An allergic reaction is possible after using Pemazyre. However, this side effect wasn’t reported in clinical trials. To learn more, see the “Side effect specifics” section below.

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

Will Pemazyre cause hair loss?

Hair loss is a common side effect of Pemazyre treatment in clinical trials. However, it’s unlikely that you’ll lose all of your hair.

You may notice that your hair is brittle or thinning. Hair loss can include all body hair, including eyebrows, underarms, legs or arms, and pubic hair. This typically starts 2–3 weeks after you begin treatment. Your hair will generally start to grow back soon after you stop treatment with Pemazyre.

Talk with your doctor if you have questions about hair loss during Pemazyre treatment.

What are the long-term side effects of Pemazyre?

There are no known long-term side effects of Pemazyre. Most of Pemazyre’s side effects will improve or go away soon after you stop taking the drug. Some side effects, such as hair loss or nail problems,* may take longer to return to usual after stopping treatment.

Retinal pigment epithelial detachment hasn’t been reported after stopping treatment with Pemazyre. But in some cases, this side effect can have long lasting impacts on your vision, even with treatment.

If you’re concerned about long-term side effects with Pemazyre or have questions about how long side effects may last, talk with your doctor or pharmacist.

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

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

Nail problems

Nail problems are a common side effect of Pemazyre in clinical trials. You may not notice changes in fingernails or toenails until you have been taking the drug for weeks or months. The most commonly reported nail changes include:

  • discoloration
  • brittleness
  • splitting or falling off
  • infection of the nail or skin around the nail

What you can do

To reduce the risk of nail problems, try to keep your nails clean and dry. It’s best to wear loose-fitting socks and footwear to help prevent added friction or pressure to your toenails. Use a moisturizer on your hands and feet daily. Your doctor can tell you which lotions, creams, or gels to use.

If you notice nail problems, try to avoid biting your nails or cutting them too short. You can use nail polish, but do not use fake nails. It’s important to limit the use of nail polish removers, as these can dry and weaken your nails.

If you do need to use nail polish remover, choose one that is acetone-free. Talk with your doctor if nail problems are bothersome or become severe. Your doctor may recommend other ways to help manage these side effects.

Hyperphosphatemia

Hyperphosphatemia is a common side effect of Pemazyre in clinical trials. Hyperphosphatemia is when you have too much phosphate in your blood. If phosphate levels are too high, it can make your bones weak. It may also cause mineral deposits in your body, which can increase your risk of heart attack or stroke. Often there are no symptoms with this side effect.

It’s important to notify your doctor if you notice symptoms of hypophosphatemia, which can include:

  • muscle cramps
  • numbness or tingling around your mouth

What you can do

Your doctor will monitor your blood phosphate levels during treatment with Pemazyre. If your phosphate levels are too high, your doctor may recommend a change in diet, prescribe a phosphate-lowering medication, or adjust your Pemazyre therapy if needed.

Contact your doctor right away if you notice any symptoms of hyperphosphatemia.

Allergic reaction

As with most drugs, Pemazyre can cause an allergic reaction in some people. However, this side effect wasn’t reported in clinical trials.

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 taking Pemazyre. However, 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 you take Pemazyre. This drug may not be the right treatment for you if you have certain medical conditions or other factors that affect your health. These are considered drug-condition or drug-factor interactions. The conditions and factors to consider include:

Vision or eye problems. If you have retinal pigment epithelial detachment or another eye condition, you may be at a higher risk of your condition worsening. Talk with your doctor to determine if Pemazyre is the right treatment option for you.

Severe kidney or liver problems. The kidney and liver help remove drugs from your body. If you have severe kidney or liver problems, such as chronic kidney disease, it will be harder for your body to remove Pemazyre from your system. If you have liver or kidney problems, your doctor may recommend a lower dose of Pemazyre.

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

Pregnancy or breastfeeding. If you’re pregnant or breastfeeding your child, you should not take Pemazyre. This drug can cause pregnancy loss and may cause side effects in a breastfed child. Be sure to tell your doctor if you’re pregnant or breastfeeding. They can let you know about other treatment options for your condition. If you or your partner are able to become pregnant, your doctor will recommend using birth control during treatment with Pemazyre.

Alcohol consumption. There is no known interaction between alcohol and Pemazyre. Drinking alcohol may worsen some side effects of Pemazyre, such as mouth sores. Your doctor may recommend that you avoid or limit how much alcohol you drink. If you have any questions about alcohol consumption while taking Pemazyre, talk with your doctor or pharmacist.

Treatment with Pemazyre can cause mild and serious side effects. Talk with your doctor if you develop side effects that are serious or bothersome.

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

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

  • More information about Pemazyre. For details about other aspects of Pemazyre, refer to this article.
  • A look at your condition. For details about certain cancers, see our cancer hub.

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.