Pemazyre (pemigatinib) is a prescription drug that’s used to treat bile duct cancer and myeloid lymphoid neoplasms (MLN) with certain genetic markers. Pemazyre comes as a tablet that you swallow.

For adults with bile duct cancer, Pemazyre may be prescribed if the cancer:

  • has a genetic mutation for the fibroblast growth factor receptor (FGFR) protein
  • has spread to other areas in the body or has spread to nearby tissues but cannot be surgically removed
  • has previously been treated with other cancer medications

And for adults with MLN, Pemazyre may be prescribed if the cancer:

  • has a genetic mutation for the FGFR protein
  • hasn’t been successfully treated with prior cancer medications or has returned after being treated in the past

To learn more about Pemazyre’s uses, see the “What is Pemazyre used for?” section below.

Pemazyre basics

Pemazyre contains the active ingredient pemigatinib. (An active ingredient is what makes a drug work.) It’s a type of targeted therapy.

Pemazyre is a brand-name medication. A generic version of the drug isn’t currently available.

Like most drugs, Pemazyre may cause mild or serious side effects. The lists below describe some of the more common side effects that Pemazyre may cause. These lists don’t include all possible side effects.

Keep in mind that side effects of a drug can depend on:

  • your age
  • other health conditions you have
  • other medications you take

Your doctor or pharmacist can tell you more about the potential side effects of Pemazyre. They can also suggest ways to help reduce side effects.

Mild side effects

Here’s a list of some of the mild side effects that Pemazyre can cause. Side effects might differ slightly depending on whether you’re taking Pemazyre for bile duct cancer or myeloid lymphoid neoplasms. To learn about other mild side effects, talk with your doctor or pharmacist or read Pemazyre’s prescribing information.

Mild side effects of Pemazyre that have been reported include:

Mild side effects of many drugs may go away within a few days to a couple of weeks. But if they become bothersome, talk with your doctor or pharmacist.

* To learn more about this side effect, see the “Allergic reaction” section below.

Serious side effects

Serious side effects from Pemazyre can occur. If you have serious side effects from Pemazyre, call your doctor right away. But if you think you’re having a medical emergency, you should call 911 or your local emergency number.

Serious side effects of Pemazyre that have been reported include:

* To learn more about this side effect, see the “Allergic reaction” section below.

Allergic reaction

Some people may have an allergic reaction to Pemazyre.

Symptoms of a mild allergic reaction can include:

  • skin rash
  • itchiness
  • flushing (temporary warmth, redness, or deepening of skin color)

A more severe allergic reaction is rare but possible. Symptoms of a severe allergic reaction can include swelling under your skin, usually in your eyelids, lips, hands, or feet. They can also include swelling of your tongue, mouth, or throat, which can cause trouble breathing.

Call your doctor right away if you have an allergic reaction to Pemazyre. But if you think you’re having a medical emergency, call 911 or your local emergency number.

Your doctor will recommend the dosage of Pemazyre that’s right for you. Below are commonly used dosages, but always take the dosage your doctor prescribes.

Form and strengths

Pemazyre is available as an oral tablet in three strengths: 4.5 milligrams (mg), 9 mg, and 13.5 mg.

Recommended dosages

Your dosage of Pemazyre will depend on what type of cancer you have. Your doctor will recommend the dosage of Pemazyre that’s right for you.

Dosage for bile duct cancer

For treatment of bile duct cancer, your doctor will likely prescribe a dosage of 13.5 mg once per day for 14 days. Then, you won’t take Pemazyre for 7 days. This pattern creates a 21-day cycle: 14 days on Pemazyre and 7 days off Pemazyre. You’ll repeat this cycle as directed by your doctor. Your doctor may change your dosage based on side effects you may have.

Dosage for myeloid lymphoid neoplasms

For treatment of myeloid lymphoid neoplasms, your doctor will likely prescribe a dosage of 13.5 mg once per day. Your doctor may change your dosage if you experience side effects.

Questions about taking Pemazyre

Below are some common questions about taking Pemazyre.

  • Can Pemazyre be chewed, crushed, or split? No, you should not chew, crush, dissolve, or split Pemazyre tablets. You should swallow them whole. If you have trouble swallowing pills, you can ask your doctor or pharmacist for advice.
  • Should I take Pemazyre with food? You may take Pemazyre with or without food.
  • Is there a best time of day to take Pemazyre? You can take Pemazyre at any time of day, but it’s best to take it around the same time each day. This helps keep a consistent level of the drug in your body, which helps Pemazyre work effectively.
  • What if I miss a dose of Pemazyre? If you miss a dose of Pemazyre, take it as soon as you remember. But if it’s been more than 4 hours, skip the dose. You should not take two doses at once to make up for a missed dose. Doing so could raise your risk of side effects. And if you vomit after taking your scheduled dose, do not take another dose. Take your next dose at its regularly scheduled time.
  • Will I need to use Pemazyre long term? Possibly. You and your doctor will work together to determine how long you’ll take Pemazyre.

Overdose

Do not take more Pemazyre than your doctor prescribes. Using more than this can lead to harmful effects.

What to do in case you take too much Pemazyre

Call your doctor if you think you’ve taken too much Pemazyre. You can also call 800-222-1222 to reach America’s Poison Centers or use its online resource. But if you have severe symptoms, immediately call 911 or your local emergency number. Or go to the nearest emergency room.

Pemazyre is used to treat bile duct cancer and myeloid lymphoid neoplasms (MLN) with certain genetic markers.

Specifically, Pemazyre is used to treat cancer cells that have a mutated (changed) fibroblast growth factor receptor (FGFR) protein. The mutated proteins increase cancer cell growth and replication. Pemazyre blocks the mutated proteins and prevents cancer cells from growing.

Bile duct cancer

The bile duct is a tube that carries bile between your liver, gallbladder, and small intestine. When cancer is present, it may block the tube and cause symptoms such as jaundice (yellowing of the skin), light-colored stool, abdominal pain, and dark-colored urine.

If you have bile duct cancer with a mutated FGFR protein, your doctor may recommend Pemazyre after trying other treatments. They may prescribe Pemazyre if the cancer has spread to nearby tissues and cannot be surgically removed. Or if the cancer has spread to other areas of the body.

Note: For treatment of bile duct cancer, Pemazyre received accelerated approval from the Food and Drug Administration (FDA) in April 2020. Accelerated approval is based on information from early clinical studies. The FDA will make a decision about full approval after more studies are completed.

Myeloid lymphoid neoplasms

With MLN, genetic mutations in the blood stem cells cause uncontrolled growth of certain blood cells. These mutated cells may accumulate in the bone marrow, blood, and other tissues, such as the spleen and lymph nodes. MLN may cause symptoms such as fatigue, weight loss, sweating, and fever.

If the genetic mutation is in the FGFR protein, your doctor may recommend Pemazyre. It’s typically prescribed when another medication hasn’t worked or when the cancer has returned following an earlier treatment.

If you have questions about possible treatment with Pemazyre, talk with your doctor.

Below is important information you should consider before taking Pemazyre.

Interactions

Taking a drug with certain medications, vaccines, foods, and other things can affect how the drug works. These effects are called interactions.

Pemazyre can interact with several other medications. It can also interact with certain supplements as well as certain foods.

Before taking Pemazyre, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.

Drug interactions

Below is a list of medications that can interact with Pemazyre. This list doesn’t contain all drugs that may interact with Pemazyre. If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.

Drug group or drug nameDrug examples
certain drugs that slow down the CYP3A4 enzyme*• itraconazole (Sporanox, Tolsura)
clarithromycin
certain drugs that speed up the CYP3A4 enzyme*• rifampin (Rifadin, Rimactane)
carbamazepine (Carbatrol, Equetro, Tegretol, Teril, Epitol)

* Cytochrome P450 3A4 (CYP3A4) is an enzyme in the liver that helps to break down certain drugs, including Pemazyre.

Other interactions

Pemazyre can also interact with other substances, such as:

  • Vitamins and supplements: Pemazyre interacts with St. John’s wort. Your doctor will likely recommend that you avoid taking this supplement during your Pemazyre treatment.
  • Foods: Pemazyre interacts with grapefruit and grapefruit juice. Your doctor will likely recommend that you do not consume grapefruit products during your Pemazyre treatment.
  • Alcohol: Alcohol is not known to interact with Pemazyre. However, alcohol may worsen certain side effects of Pemazyre, such as mouth ulcers and dehydration. Also, a study found drinking alcohol may make cancer treatments such as Pemazyre less effective.

Before starting Pemazyre treatment, talk with your doctor and pharmacist. Tell them about all prescription, over-the-counter, and other drugs you take. Also, tell them about any vitamins, herbs, and supplements you take. Sharing this information can help you avoid potential interactions.

If you have questions about drug interactions that may affect you, talk with your doctor or pharmacist.

Pregnancy and breastfeeding

You should not take Pemazyre during pregnancy or while breastfeeding.

At this time, there haven’t been any human studies of Pemazyre during pregnancy. But due to the way the drug works, it may cause problems with fetal development (commonly known as birth defects). It may also result in pregnancy loss. If you can become pregnant, your doctor will have you take a pregnancy test to confirm that you’re not pregnant before starting Pemazyre treatment.

It’s not known whether Pemazyre may be present in breast milk or what effects the drug may have on a child who is breastfed. But it’s not recommended to breastfeed while taking Pemazyre and for at least 1 week after stopping treatment.

Birth control

It’s recommended that females* who can become pregnant use birth control during treatment with Pemazyre and for at least 1 week after taking the last dose. Males* with partners who can become pregnant should also use contraception during treatment and for at least 1 week after the last dose.

* In this article, we use the terms “male” and “female” to refer to someone’s sex assigned at birth. For information about the difference between sex and gender, see this article.

Warnings

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

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

Find answers below to some commonly asked questions about Pemazyre.

How long does it take Pemazyre to start working?

Pemazyre starts to work right after you take a dose. But it may take several weeks before your tumors become smaller or stop growing.

In studies, some people saw a reduction in tumor size within one month of starting treatment. But in other cases, it took nearly 7 months of treatment before a reduction in tumor size was noted.

If you have other questions about what to expect from Pemazyre treatment, talk with your doctor.

How does Pemazyre compare with Keytruda?

Both Pemazyre and pembrolizumab (Keytruda) are used to treat certain types of cancer. Pemazyre can only be taken by adults. Keytruda, on the other hand, can also be prescribed to children with certain types of cancer.

Pemazyre comes as an oral tablet. Keytruda is given as an intravenous (IV) infusion* by a healthcare professional. They belong to different groups of drugs.

If you have other questions about how Pemazyre and Keytruda compare, talk with your doctor.

* An IV infusion is an injection into a vein given over time.

Is Pemazyre used for other types of cancer?

No, at this time, Pemazyre isn’t used for other types of cancer.

To learn more about treatment options for other types of cancer, talk with your doctor.

Whether you have health insurance or not, cost may be a factor when you’re considering Pemazyre.

Here are a few things to consider regarding cost:

  • Cost information and savings coupons: You can visit Optum Perks* to get price estimates of what you’d pay for Pemazyre when using coupons from the site.
  • Savings program: If you have questions about how to pay for your prescription, talk with your doctor or pharmacist. A program called IncyteCARES for Pemazyre may be available.

You can also check out this article to learn more about saving money on prescriptions.

* Optum Perks is a sister site of Healthline. Optum Perks coupons cannot be used with insurance copays or benefits.

Other drugs may be available that can treat bile duct cancer or myeloid lymphoid neoplasms (MLN). If you’d like to explore an alternative to Pemazyre, talk with your doctor. They can tell you about other medications that might work well for you.

For example, the following drugs can be prescribed to treat certain types of bile duct cancer:

  • futibatinib (Lytgobi)
  • ivosidenib (Tibsovo)
  • durvalumab (Imfinzi)

Other drugs, such as pembrolizumab (Keytruda) and imatinib (Gleevec), are prescribed to treat certain blood cancers. But Pemazyre is the only drug that treats MLN with mutated fibroblast growth factor receptor (FGFR) proteins the way it does. Talk with your doctor if you’re interested in other medications for your condition.

If you have questions about taking Pemazyre, talk with your doctor or pharmacist. Questions you may want to ask include:

  • Will I lose my hair while taking Pemazyre?
  • How and when will my doctor change my dosage?
  • What tests will confirm that Pemazyre is working?
  • How is Pemazyre different from chemotherapy?

To get information on different conditions and tips for improving your health, subscribe to any of Healthline’s newsletters. You may also want to check out the online communities at Bezzy. It’s a place where people with certain conditions can find support and connect with others.

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.