Tukysa is a brand-name prescription medication. It’s approved to treat a certain form of advanced breast cancer in adults.

Specifically, Tukysa is approved to treat breast cancer that’s HER2-positive (HER2+)* and is either:

  • locally advanced (has spread into nearby tissues) and unresectable (can’t be removed with surgery), or
  • metastatic (has spread to other parts of the body)

Tukysa is approved for use in adults who’ve already taken one or more anti-HER2 treatments in the past for their cancer. For its approved uses, Tukysa is given in combination with two other cancer drugs: trastuzumab (Herceptin) and capecitabine (Xeloda).

Tukysa contains the active drug tucatinib. It’s a targeted therapy for HER2+ breast cancer. Targeted therapies work by blocking specific proteins that help cancer cells grow and multiply. (Cells that multiply are making more cells.)

Tukysa comes as a tablet that’s taken by mouth twice a day. It’s available in two strengths: 50 mg and 150 mg.

* HER2+ cancer has abnormally high levels of a protein called HER2 that encourages cancer cell growth.

FDA approval

In April 2020, Tukysa was approved by the Food and Drug Administration (FDA) for use.

Tukysa belongs to a new class of drugs for treating HER2+ breast cancer called tyrosine kinase inhibitors. (A class of drugs is a group of medications that work in a similar way.) Tukysa works in a slightly different way than other drugs in this class work. This drug adds to the treatment options available to people with HER2+ breast cancer when other medications have stopped working.

Effectiveness

In a clinical study, Tukysa was effective in treating advanced HER2+ breast cancer. In the study, some people took Tukysa, while other people took a placebo. (A placebo is a treatment containing no active drug.) Both groups of people also took Xeloda and Herceptin.

In this study, compared with people who took the placebo:

  • after 1 year, people who took Tukysa were 46% less likely to have their cancer progress (get worse or spread further in their body)
  • after 2 years, people who took Tukysa were 34% less likely to die

For more information about Tukysa’s effectiveness, see the section “Tukysa uses” below.

Tukysa is available only as a brand-name medication. It’s not currently available in generic form. (A generic drug is an exact copy of the active drug in a brand-name medication.)

The Tukysa dosage your doctor prescribes will depend on several factors. These include:

  • how well your liver works
  • if you take certain other medications
  • if you develop certain side effects from the drug

The following information describes dosages that are commonly used or recommended. However, be sure to take the dosage your doctor prescribes for you. Your doctor will determine the best dosage to fit your needs.

Drug forms and strengths

Tukysa comes as a tablet that’s taken by mouth. It’s available in two strengths: 50 milligrams (mg) and 150 mg.

Dosage for advanced breast cancer

The usual dosage of Tukysa for advanced HER2-positive (HER2+)* breast cancer is 300 mg taken twice a day.

If you have problems with your liver, your doctor may recommend that you take a dosage of Tukysa that’s lower than usual.

Your doctor may also lower your dosage of Tukysa or have you take a break from treatment if you develop certain side effects from the drug. These side effects may include diarrhea.

* HER2+ cancer has abnormally high levels of a protein called HER2 that encourages cancer cell growth.

What if I miss a dose?

If you miss a dose of Tukysa just skip the missed dose. Then take your next dose as scheduled. Don’t take an extra dose to make up for a missed dose.

To help make sure that you don’t miss a dose, try setting a reminder on your phone. A medication timer may be useful, too.

Will I need to use this drug long term?

Tukysa is meant to be used as a long-term treatment. If you and your doctor determine that Tukysa is safe and effective for you, you’ll likely take it long term.

You’ll probably take Tukysa for as long as the drug keeps your cancer from worsening and the side effects remain manageable.

Tukysa can cause mild or serious side effects. The following lists contain some of the key side effects that may occur while taking Tukysa. These lists don’t include all possible side effects.

For more information on the possible side effects of Tukysa, talk with your doctor or pharmacist. They can give you tips on how to deal with any side effects that may be bothersome.

Note: The Food and Drug Administration (FDA) tracks side effects of drugs it has approved. If you would like to report to the FDA a side effect you’ve had with Tukysa, you can do so through MedWatch.

Mild side effects

Mild side effects of Tukysa can include:*

  • nausea and vomiting
  • fatigue (lack of energy)
  • stomatitis (painful sores or ulcers in your mouth)
  • hand-foot syndrome (a condition that causes redness, itching, or peeling of the skin on your hands and feet)
  • decreased appetite
  • abdominal (belly) pain
  • headache
  • anemia (low red blood cell count)
  • rash

Most of these side effects may go away within a few days or a couple of weeks. But if they become more severe or don’t go away, talk with your doctor or pharmacist.

* This is a partial list of mild side effects from Tukysa. To learn about other mild side effects, talk with your doctor or pharmacist, or see Tukysa’s Important Facts.

Serious side effects

Serious side effects from Tukysa aren’t common, but they can occur. Call your doctor right away if you have serious side effects. Call 911 if your symptoms feel life threatening or if you think you’re having a medical emergency.

Serious side effects, which are explained in more detail below in “Side effect details,” include:

Side effect details

You may wonder how often certain side effects occur with this drug. Here’s some detail on certain side effects this drug may cause.

Diarrhea

You may have diarrhea while you’re taking Tukysa. In fact, diarrhea is the most common side effect of this drug. It’s also one of the most common side effects of both Xeloda and Herceptin, which are used with Tukysa for breast cancer treatment.

How common is diarrhea with Tukysa?

In a clinical study, diarrhea occurred in:

  • 81% of people who took Tukysa with Xeloda and Herceptin
  • 53% of people who took a placebo (treatment with no active drug) with Xeloda and Herceptin

Although diarrhea is common, it can quickly become serious. For example, diarrhea may lead to dehydration (low fluid level), low blood pressure, and kidney damage. And in rare cases, these problems can be fatal.

In a clinical study, serious cases of diarrhea occurred in:

  • 12.5% of people who took Tukysa with Xeloda and Herceptin
  • 9% of people who took a placebo with Xeloda and Herceptin

In the same clinical study, in people with diarrhea:

  • Tukysa dosages were lowered in 6% of people
  • Tukysa was stopped in 1% of people

What to do for diarrhea with Tukysa

If you have diarrhea while you’re taking Tukysa, see your doctor right away. They may prescribe a medication to help reduce your diarrhea. In addition, depending on how severe your diarrhea is, your doctor may recommend that you stop taking Tukysa for a while.

If or when you start taking Tukysa again, your doctor may lower your dosage of the drug.

If you have diarrhea that’s very severe while you’re taking Tukysa, you may need to permanently stop taking the drug.

It’s important to drink plenty of fluids to avoid dehydration If you have diarrhea with Tukysa. To do this, try sipping on fluids throughout the day, especially after having bowel movements. Sports drinks can also be helpful, because they contain salts, such as sodium and potassium, that are sometimes lost through diarrhea.

Nausea and vomiting

It’s possible to have nausea and vomiting while you’re taking Tukysa. This is a common problem that’s caused by many cancer treatments, including Tukysa. It’s also a common problem with Xeloda and Herceptin, which are used in combination with Tukysa for breast cancer treatment.

How common are nausea and vomiting with Tukysa?

In a clinical study, nausea was reported in:

  • 58% of people who took Tukysa with Xeloda and Herceptin
  • 44% of people who took a placebo (treatment with no active drug) with Xeloda and Herceptin

Also in the study, vomiting was reported in:

  • 36% of people who took Tukysa with Xeloda and Herceptin
  • 25% of people who took a placebo with Xeloda and Herceptin

What to do for nausea and vomiting with Tukysa

If you frequently have nausea or vomiting with Tukysa, talk with your doctor. They may prescribe medication to help reduce your symptoms. They can also recommend other ways to help manage this problem.

If you vomit after taking a dose of Tukysa, don’t take an extra dose of the drug. Instead, just take your next dose as scheduled.

General tips that may be helpful in preventing or reducing nausea and vomiting include:

  • frequently eating small amounts of food instead of having larger meals less often
  • avoiding fatty or greasy foods
  • frequently sipping on clear liquids throughout the day

Hand-foot syndrome

You may have a side effect called hand-foot syndrome while you’re taking Tukysa. This condition is also called palmar-plantar erythrodysesthesia syndrome.

Hand-foot syndrome is common in people taking Tukysa. It’s also a common side effect of Xeloda, which is used in combination with Tukysa for breast cancer treatment.

How common is hand-foot syndrome with Tukysa?

In a clinical study, hand-foot syndrome was reported in:

  • 63% of people who took Tukysa with Xeloda and Herceptin
  • 53% of people who took a placebo (treatment with no active drug) with Xeloda and Herceptin

Causes and symptoms of hand-foot syndrome

Hand-foot syndrome is caused when a medication leaks out of small blood vessels in your hands and feet. Then the medication causes damage to the tissue it leaks into.

Hand-foot syndrome can cause the following symptoms, which affect the palms of your hands and soles of your feet:

  • redness
  • rash
  • swelling
  • blisters
  • peeling
  • tenderness
  • tingling, burning, or itching
  • pain
  • trouble walking or using your hands

What to do for hand-foot syndrome with Tukysa

If you have any symptoms of hand-foot syndrome while you’re taking Tukysa, talk with your doctor. They can recommend ways to help manage this side effect.

If your symptoms are severe, your doctor may lower your dosage of Tukysa. Or they may recommend that you take a break from treatment with the drug.

Tips to help prevent hand-foot syndrome with Tukysa

To help prevent hand-foot syndrome with Tukysa treatment, try avoiding:

  • prolonged heat exposure on your hands or feet, such as when washing the dishes or taking hot baths
  • using hand tools, such as knives or a hammer
  • rubbing your hands and feet
  • exercise activities that put lots of impact on your feet, such as running
  • wearing tight shoes

In addition, using a mild moisturizer on your hands and feet may help to prevent this condition. But be sure to apply the moisturizer gently.

Inflammation in your mouth and lips

You may have stomatitis while you’re taking Tukysa. With stomatitis, you have inflammation on your lips and inside your mouth. Stomatitis may cause the following symptoms:

  • sores or ulcers in your mouth
  • ulcers on your lips
  • swelling in your tongue
  • ulcers or blisters on your tongue
  • pain in your mouth
  • pain when swallowing

Stomatitis is a common side effect of Tukysa. It’s also a common side effect of Xeloda, which is used in combination with Tukysa for breast cancer treatment.

In a clinical study, stomatitis was reported in:

  • 32% of people who took Tukysa with Xeloda and Herceptin
  • 21% of people who took a placebo (treatment with no active drug) with Xeloda and Herceptin

If you have any of these symptoms while you’re taking Tukysa, talk with your doctor. They may be able to recommend ways to help manage your symptoms.

Liver damage

Tukysa can sometimes cause liver damage, which is also called hepatotoxicity. So you may have problems with how well your liver works while you’re taking Tukysa. Symptoms of liver problems can include:

  • jaundice (yellowing of your skin and the whites of your eyes)
  • dark urine or pale stools
  • pain in your upper right abdomen (belly)
  • itching
  • bruising or bleeding more easily than usual
  • fatigue (lack of energy)

How common is liver damage with Tukysa?

In a clinical study, hepatotoxicity was reported in:

  • 42% of people who took Tukysa with Xeloda and Herceptin
  • 24% of people who took a placebo (treatment with no active drug) with Xeloda and Herceptin

Monitoring for liver damage

While you’re taking Tukysa, you’ll have frequent blood tests to check the health of your liver. These blood tests are called liver function tests (LFTs). They measure the level of liver enzymes in your blood.

Liver enzymes are proteins that your liver uses to carry out its normal functions. Damage to liver cells causes liver enzymes to be released into your blood. If your blood test results show raised levels of liver enzymes, your liver may be damaged.

What to do for liver damage with Tukysa

If you have any symptoms of liver damage while you’re taking Tukysa, see your doctor right away. Your doctor may order LFTs to assess the health of your liver.

If you do have liver damage, your doctor may recommend that you stop taking Tukysa for a while. And if or when you start taking Tukysa again, your doctor may lower your dosage of the drug.

But if you have severe liver damage from Tukysa, your doctor may recommend that you permanently stop taking the drug.

The Food and Drug Administration (FDA) approves prescription drugs such as Tukysa to treat certain conditions. Tukysa may also be used off-label for other conditions. Off-label use is when a drug that’s approved to treat one condition is used to treat a different condition.

Tukysa for advanced breast cancer

Tukysa is FDA-approved to treat a certain form of advanced breast cancer in adults. Specifically, Tukysa is approved to treat breast cancer that’s HER2-positive (HER2+)* and is either:

  • locally advanced (has spread into nearby tissues) and unresectable (can’t be removed with surgery), or
  • metastatic (has spread to other parts of the body)

Tukysa is approved for use in adults who’ve already taken one or more anti-HER2 treatments in the past for their cancer. Examples of these treatments include:

  • trastuzumab (Herceptin, Herceptin Hylecta)
  • pertuzumab (Perjeta)
  • trastuzumab emtansine (Kadcyla)

For its approved uses, Tukysa is given in combination with two other cancer drugs: trastuzumab (Herceptin) and capecitabine (Xeloda).

Tukysa is a targeted therapy for HER2+ breast cancer. Targeted therapies work by blocking specific proteins that help cancer cells grow and multiply. (Cells that multiply are making more cells.)

* HER2+ cancer has abnormally high levels of a protein called HER2 that encourages cancer cell growth.

Effectiveness for advanced breast cancer

In a clinical study, Tukysa was effective in treating advanced HER2+ breast cancer. In the study, some people took Tukysa, while other people took a placebo. (A placebo is a treatment containing no active drug.) Both groups of people also took Xeloda and Herceptin.

In this study, compared with people who took the placebo:

  • after 1 year, people who took Tukysa were 46% less likely to have their cancer progress (get worse or spread further in their body)
  • after 2 years, people who took Tukysa were 34% less likely to die

In addition, the study showed that:

  • for at least half of the people who took Tukysa, their cancer didn’t get worse for at least 7.8 months
  • for at least half of the people who took the placebo, their cancer didn’t get worse for at least 5.6 months
  • at least half of the people who took Tukysa lived for 21.9 months or longer after joining the study
  • at least half of the people who took the placebo lived for 17.4 months or longer after joining the study

Tukysa and children

Tukysa isn’t FDA-approved for use in children. Keep in mind that the type of cancer that Tukysa treats doesn’t affect children. And Tukysa hasn’t been studied in children with any other type of cancer.

Tukysa is approved to treat advanced HER2-positive (HER2+) breast cancer. HER2+ cancer has abnormally high levels of a protein called HER2 that encourages cancer cell growth.

For this condition, Tukysa is approved for use in combination with both trastuzumab (Herceptin) and capecitabine (Xeloda).

Tukysa with Herceptin

Like Tukysa, Herceptin is also a targeted therapy for HER2+ breast cancer. Targeted therapies work by blocking specific proteins that help cancer cells grow. Both Tukysa and Herceptin block the effect of the HER2 protein. But these drugs work in slightly different ways in your body.

Herceptin blocks part of the HER2 protein that sits on the surface of the breast cancer cells. Tukysa, on the other hand, blocks part of the HER2 protein that’s inside the breast cancer cells.

While Tukysa is taken by mouth, Herceptin is given by intravenous (IV) infusion. With an IV infusion, the drug is dripped into your vein over a period of time. (Note: Herceptin Hylecta is a different form of Herceptin that is given as a subcutaneous injection [an injection under the skin]).

Tukysa tablets are taken twice daily, but Herceptin infusions are given from once a week to once every 21 days, depending on the formulation of the drug used. You’ll receive these infusions at your doctor’s office or healthcare facility. Herceptin IV infusions typically last for about 30 to 90 minutes. Herceptin Hylecta injections take 2 to 5 minutes to give.

Tukysa with Xeloda

Unlike Tukysa, which is a targeted therapy drug, Xeloda is a chemotherapy drug. Chemotherapy works by killing cells in your body that are rapidly multiplying (making more cells). Because some healthy cells multiply rapidly, chemotherapy affects them as well as cancer cells.

But like Tukysa, Xeloda also comes as tablets that are taken by mouth twice each day. You’ll take Tukysa every day. However, you’ll take Xeloda in 21-day cycles, where you take it every day for 14 days, followed by a 7-day break.

Xeloda needs to be taken within 30 minutes after you’ve eaten a meal in the morning and evening. To make dosing convenient, you can take Tukysa at the same time as you take Xeloda. But Tukysa can actually be taken with or without food.

Treatment cycle schedule with Tukysa plus Herceptin and Xeloda

Treatment with Tukysa plus Herceptin and Xeloda is given on a 21-day cycle. Each 21-day treatment cycle will typically be as follows:

  • Day 1. On this day, you’ll receive a Herceptin IV infusion or subcutaneous injection, plus you’ll take Tukysa and Xeloda twice daily by mouth.
  • Days 2 to 14. On these days, you’ll take both Tukysa and Xeloda twice daily by mouth.
  • Days 15 to 21. One these days, you’ll take Tukysa twice daily by mouth. Xeloda is stopped during this period of time.

You’ll continue to take these three drugs on this schedule for as long as your doctor recommends.

There aren’t any known interactions between Tukysa and alcohol. However, drinking alcohol could worsen certain side effects of Tukysa, such as:

  • nausea
  • diarrhea
  • headache
  • fatigue (lack of energy)

In addition, both alcohol and Tukysa can affect your liver function.

If you want to drink alcohol while you’re taking Tukysa, talk with your doctor about how much is safe to drink.

Tukysa can interact with several other medications. It can also interact with certain supplements.

Different interactions can cause different effects. For instance, some interactions can interfere with how well a drug works. Other interactions can increase side effects or make them more severe.

Tukysa and other medications

Below is a list of medications that can interact with Tukysa. These lists don’t contain all the drugs that may interact with Tukysa.

Before taking Tukysa, 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.

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

Tukysa and certain drugs used to treat infection

Taking Tukysa with certain drugs used to treat infection can increase your liver’s breakdown of Tukysa. This can lower the level of Tukysa in your body, making the drug less effective for you.

Examples of drugs used to treat infections that could lower the level of Tukysa in your body include:

  • rifabutin (Mycobutin)
  • rifampin (Rifadin)
  • rifapentine (Priftin)

Typically, these medications should be avoided while you’re taking Tukysa. If you have an infection that would usually be treated with one of these drugs, you doctor will likely recommend a different drug to treat the infection.

Tukysa and certain seizure medications

Taking Tukysa with certain seizure medications can increase your liver’s breakdown of Tukysa. This can lower the level of Tukysa in your body, making the drug less effective for you.

Examples of seizure medications that could lower the level of Tukysa in your body include:

Typically, these medications should be avoided while you’re taking Tukysa. If you take one of these seizure drugs, your doctor will likely recommend a different seizure medication for you while you’re using Tukysa.

Tukysa and certain drugs that can increase Tukysa levels

Taking certain drugs with Tukysa can prevent your liver from breaking down Tukysa. This can increase the level of Tukysa in your body, which raises your risk of side effects from the drug.

Examples of drugs that could increase Tukysa levels in your body include:

Typically, gemfibrozil should be avoided while you’re taking Tukysa. If you do take gemfibrozil, your doctor will likely recommend switching to a different medication to lower your lipid levels. But if you must take gemfibrozil, your doctor will decrease your dose of Tukysa to 100 mg twice daily by mouth.

If you take any of the other drugs listed above with Tukysa, your doctor will closely monitor you for side effects of Tukysa.

Tukysa and certain drugs whose levels may be increased

If taken together, Tukysa can slow your body’s breakdown of certain other drugs. This can lead to increased levels of the other drugs in your body. And it can also increase your risk of side effects from those other drugs.

Examples of drugs whose levels may be increased if they’re taken with Tukysa include:

If you take any of the drugs listed above, talk with your doctor about whether it’s safe for you to take it with Tukysa. In some cases, your doctor may recommend taking a dosage of these drugs that’s lower than usual.

Tukysa and herbs and supplements

Tukysa is known to interact with an herb called St. John’s wort. This interaction is reviewed below. But to be safe, talk with your doctor before taking any herbs or supplements with Tukysa. Your doctor can recommend whether it’s safe for you to do so.

Tukysa and St. John’s wort

Taking St. John’s wort (Hypericum perforatum) with Tukysa may lower the level of Tukysa in your body. And this could make Tukysa less effective for you.

Because of this interaction, you shouldn’t take St. John’s wort with Tukysa.

Tukysa and foods

There aren’t any foods that have been specifically reported to interact with Tukysa. If you have any questions about eating certain foods with Tukysa, talk with your doctor.

As with all medications, the cost of Tukysa can vary. To find current prices for Tukysa tablets in your area, check out WellRx.com.

The cost you find on GoodRx.com is what you may pay without insurance. The actual price you’ll pay depends on your insurance plan, your location, and the pharmacy you use.

It’s important to note that you’ll have to get Tukysa at a specialty pharmacy. This type of pharmacy is authorized to carry specialty medications. These are drugs that may be expensive or may require help from healthcare professionals to be used safely and effectively.

Before approving coverage for Tukysa, your insurance company may require you to get prior authorization. This means that your doctor and insurance company will need to communicate about your prescription before the insurance company will cover the drug. The insurance company will review the prior authorization request and decide if the drug will be covered.

If you’re not sure if you’ll need to get prior authorization for Tukysa, contact your insurance company.

Financial and insurance assistance

If you need financial support to pay for Tukysa, or if you need help understanding your insurance coverage, help is available.

Seattle Genetics, Inc., the manufacturer of Tukysa, offers a program called SeaGen Secure. Through this program, you can find out about insurance coverage of Tukysa. And you can also learn about cost savings options that are available.

For more information and to find out if you’re eligible for support, call 855-4SECURE (855-473-2873) or visit the program website.

Generic version

Tukysa isn’t available in a generic form. A generic drug is an exact copy of the active drug in a brand-name medication. Generics tend to cost less than brand-name drugs.

Other drugs are available that can treat advanced or metastatic HER2-positive (HER2+) breast cancer.*

Some may be a better fit for you than others. If you’re interested in finding an alternative to Tukysa, talk with your doctor. They can tell you about other medications that may work well for you.

Examples of other drugs that may be used to treat advanced or metastatic HER2+ breast cancer include:

* With advanced and metastatic breast cancer, the cancer has spread outside of your breast. HER2+ breast cancer has abnormally high levels of a protein called HER2 that promotes cancer cell growth.

You may wonder how Tukysa compares with other medications that are prescribed for similar uses. Here we look at how Tukysa and Kadcyla are alike and different.

Ingredients

Tukysa contains the active drug tucatinib, which is a targeted therapy for HER2-positive (HER2+) breast cancer.* Targeted therapies work by blocking specific proteins that help cancer cells grow and multiply.

Kadcyla contains the active drug ado-trastuzumab emtansine, which is made with:

  • trastuzumab (Herceptin), another targeted therapy for HER2+ breast cancer
  • emtansine, a chemotherapy drug (traditional drug used to treat cancer)

* HER2+ breast cancer has abnormally high levels of a protein called HER2 that promotes cancer cell growth.

Uses

Tukysa is FDA-approved to treat HER2 positive breast cancer that is:

  • locally advanced (has spread into nearby tissues) and unresectable (can’t be removed with surgery), or
  • metastatic (has spread to other parts of the body)

Tukysa is used for people who’ve already taken one or more anti-HER2 treatments in the past for their cancer. For this use, Tukysa is taken in combination with two other breast cancer treatments, called trastuzumab (Herceptin) and capecitabine (Xeloda).

Kadcyla is FDA-approved to treat the following types of breast cancer:

  • HER2+ metastatic breast cancer in people who previously received both Herceptin and a taxane-containing drug. (The people may have taken these medications either separately or together.)
  • HER2+ early stage breast cancer* that needs further treatment after both presurgery therapy (with Herceptin and a taxane-containing drug) and surgery.

* With early stage breast cancer, the cancer hasn’t spread beyond the breast or the lymph nodes in the armpits.

Drug forms and administration

Tukysa comes as tablets that are taken by mouth twice daily.

Kadcyla is given by intravenous (IV) infusion once every 21 days. With an IV infusion, the drug is dripped into your vein over a period of time.

Side effects and risks

Tukysa and Kadcyla can cause some similar side effects, but some different ones as well. Below are examples of these side effects.

Mild side effects

These lists contain up to 10 of the most common mild side effects that can occur with Tukysa, with Kadcyla, or with both drugs (when taken individually).

  • Can occur with Tukysa:
    • stomatitis (painful sores or ulcers in your mouth)
    • hand-foot syndrome (a condition that causes redness, itching, or peeling on the skin of your hands and feet)
    • decreased appetite
    • anemia (low red blood cell count)
    • rash
  • Can occur with Kadcyla:
    • muscle, bone, or joint pain
    • constipation
    • diarrhea
    • nosebleeds
  • Can occur with both Tukysa and Kadcyla:
    • nausea and vomiting
    • fatigue (lack of energy)
    • headache
    • abdominal (belly) pain

Serious side effects

These lists contain examples of serious side effects that can occur with Tukysa, with Kadcyla, or with both drugs (when taken individually).

  • Can occur with Tukysa:
    • diarrhea
  • Can occur with Kadcyla:
    • severe bleeding
    • heart problems that cause a weak heartbeat*
    • lung problems, such as pneumonitis (inflammation in your lungs)
    • nerve damage that causes pain, numbness, or other sensations in your hands and feet
    • allergic reaction
  • Can occur with both Tukysa and Kadcyla:

* Kadcyla has boxed warnings for these side effects. A boxed warning is the most serious warning from the Food and Drug Administration (FDA). It alerts doctors and patients about drug effects that may be dangerous.

Effectiveness

Tukysa and Kadcyla have different FDA-approved uses, but they’re both used to treat HER2+ metastatic breast cancer.

These drugs haven’t been directly compared in clinical studies. But studies have found both Tukysa and Kadcyla to be effective in treating this form of breast cancer.

Costs

You can view cost estimates for Tukysa and Kadcyla on WellRx.com. But the actual price you’ll pay for either drug depends on your insurance plan and your location. It also depends on whether you receive the drug from a pharmacy or medical facility.

Tukysa and Kadcyla are both brand-name drugs. There are currently no generic forms of either drug. Brand-name medications usually cost more than generics.

You may wonder how Tukysa compares with other medications that are prescribed for similar uses. Here we look at how Tukysa and Perjeta are alike and different.

Ingredients

Tukysa contains the active drug tucatinib, which is a targeted therapy for HER2-positive (HER2+) breast cancer.* Targeted therapies work by blocking specific proteins that help cancer cells grow and multiply.

Perjeta contains the active drug pertuzumab. It’s also a targeted therapy for HER2+ breast cancer.

* HER2+ breast cancer has abnormally high levels of a protein called HER2 that promotes cancer cell growth.

Uses

Tukysa is FDA-approved to treat HER2 positive breast cancer that is:

  • locally advanced (has spread into nearby tissues) and unresectable (can’t be removed with surgery), or
  • metastatic (has spread to other parts of the body)

Tukysa is used for people who’ve already taken one or more anti-HER2 treatments in the past for their cancer. For this use, Tukysa is taken in combination with two other breast cancer treatments, called trastuzumab (Herceptin) and capecitabine (Xeloda).

Perjeta is approved to treat the following types of breast cancer:

  • HER2+ metastatic breast cancer in people who haven’t had anti-HER2 therapy or chemotherapy* in the past for metastatic disease. For this use, Perjeta is given with both Herceptin and docetaxel (Taxotere).
  • HER2+ breast cancer that’s inflammatory, and either early stage or locally advanced.† For this use, Perjeta is given as neoadjuvant therapy (presurgery treatment that’s used to shrink the tumor). And Perjeta is given with both Herceptin and chemotherapy.
  • HER2+ early stage breast cancer that has a high risk of recurrence.‡ For this use, Perjeta is given as adjuvant treatment (add-on treatment). It’s given with both Herceptin and chemotherapy.

*Chemotherapy describes traditional drugs used to treat cancer.
† With early stage breast cancer, the cancer hasn’t spread beyond the breast or lymph nodes in the armpits. And with locally advanced breast cancer, the cancer has spread from the breast into nearby tissues.
‡ With recurrence, the cancer comes back after improving with treatment in the past.

Drug forms and administration

Tukysa comes as tablets that are taken by mouth twice daily.

Perjeta is given by intravenous (IV) infusion once every 3 weeks. With an IV infusion, the drug is dripped into your vein over a period of time.

Side effects and risks

Tukysa and Perjeta can cause very similar side effects, but some different ones as well. Below are examples of these side effects.

Mild side effects

These lists contain up to 10 of the most common mild side effects that can occur with Tukysa, with Perjeta, or with both drugs (when taken individually).

  • Can occur with Tukysa:
    • hand-foot syndrome (a condition that causes redness, itching, or peeling on the skin of your hands and feet)
    • abdominal (belly) pain
  • Can occur with Perjeta:
    • hair loss
    • diarrhea
  • Can occur with both Tukysa and Perjeta:
    • nausea and vomiting
    • fatigue (lack of energy)
    • rash
    • headache
    • anemia (low red blood cell count)
    • stomatitis (painful sores or ulcers in your mouth)
    • decreased appetite

Serious side effects

These lists contain examples of serious side effects that can occur with Tukysa, with Perjeta, or with both drugs (when taken individually).

  • Can occur with Tukysa:
    • diarrhea
  • Can occur with Perjeta:
    • heart problems that cause a weak heartbeat*
    • infusion reaction, which may cause fever, headache, fatigue, or allergic reaction
    • allergic reaction
  • Can occur with both Tukysa and Perjeta:
    • few serious side effects common to both drugs

* Perjeta has a boxed warning for this side effect. This is the most serious warning from the Food and Drug Administration (FDA). It alerts doctors and patients about drug effects that may be dangerous.

Effectiveness

Tukysa and Perjeta have different approved uses, but they’re both used to treat HER2+ metastatic breast cancer.

These drugs haven’t been directly compared in clinical studies. But studies have found both Tukysa and Perjeta to be effective in treating this form of breast cancer.

Costs

You can view cost estimates for Tukysa and Perjeta on WellRx.com. But the actual price you’ll pay for either drug depends on your insurance plan and your location. It also depends on whether you receive the drug from a pharmacy or medical facility.

Tukysa and Perjeta are both brand-name drugs. There are currently no generic forms of either drug. Brand-name medications usually cost more than generics.

You should take Tukysa according to your doctor’s or healthcare provider’s instructions.

When to take

Tukysa should be taken twice daily, in the morning and evening. You should take your doses at the same time each day, about 12 hours apart.

To help make sure that you don’t miss a dose of Tukysa, try setting a reminder on your phone. A medication timer may be useful, too.

Taking Tukysa with food

Tukysa can be taken either with or without food.

Can Tukysa be crushed, split, or chewed?

No, don’t crush, split, or chew Tukysa. Tukysa should be swallowed whole. Don’t take tablets that are broken, cracked, or damaged in any way.

If you have trouble swallowing Tukysa whole, talk with your doctor or pharmacist.

Tukysa is used to treat advanced forms of HER2-positive (HER2+) breast cancer. HER2+ cancer is described in more detail below.

Specifically, Tukysa is approved for HER2+ breast cancer that’s either:

  • locally advanced (spread to nearby tissues) and can’t be removed with surgery, or
  • metastatic (spread to other parts of the body, such as your brain, lungs, or liver)

Tukysa is given to adults who’ve already taken one or more anti-HER2 treatments in the past for their cancer.

What happens in HER2-positive breast cancer

Breast cancer occurs when cells in your breast start to multiply uncontrollably. (Cells that multiply are making more cells.) With HER2+ breast cancer, a protein called HER2 is involved in making this process happen.

HER2 stands for human epidermal growth factor receptor 2. HER2 is a protein that’s made in all breast cells. It’s produced by the HER2 gene. HER2 proteins are receptors (attachment sites) that sit on the surface of the breast cells. They turn on pathways inside the cells that help the cells grow, multiply, and repair themselves.

Sometimes the HER2 gene can become faulty and make extra copies of itself. The extra copies of the gene cause extra HER2 proteins to be made. And these extra HER2 proteins cause cells to grow and multiply much faster than usual.

When you’re diagnosed with breast cancer, a sample of your breast tissue will be tested for HER2 status. If the tissue has higher than normal levels of either HER2 proteins or HER2 genes, the cancer is called HER2+. If the tissue doesn’t have higher than normal levels of these proteins or genes, it’s called HER2-negative (HER2–).

What Tukysa does

Tukysa is a targeted therapy for HER2+ breast cancer. Tukysa works by attaching to HER2 receptors and turning them off. This stops the HER2 receptors from turning on pathways that make cancer cells grow and multiply. This is how the drug slows the growth and spread of HER2+ breast cancer.

How long does it take to work?

Tukysa starts working on your cancer cells as soon as you’ve taken your first dose of the drug. However, you may not notice Tukysa working inside your body. This is because the drug doesn’t treat symptoms of breast cancer. It helps to stop the cancer from getting worse.

Your doctor will order certain tests during your Tukysa treatment to check to see how well the drug is working for you. If you have questions about the tests you’ll need to have during treatment, talk with your doctor.

If taken during pregnancy, Tukysa could harm a developing fetus. Because of this, you shouldn’t take Tukysa if you’re pregnant or planning to become pregnant.

Before you start taking Tukysa, you’ll need to have a pregnancy test done to make sure you’re not pregnant. And be sure to tell your doctor right away if you think you could be pregnant while you’re taking Tukysa.

Tukysa and fertility

Animal studies suggest that Tukysa could reduce fertility in men and women. (Fertility means the ability to become pregnant or cause someone to become pregnant.)

Animal studies don’t always predict what will happen in humans. However, if you’d like to plan a pregnancy, talk with your doctor before starting Tukysa. Your doctor can discuss with you the risks and benefits of using this medication.

Tukysa can harm a fetus if it’s taken during pregnancy. For more information about taking Tukysa during pregnancy, see the “Tukysa and pregnancy” section above.

If you’re sexually active and you or your partner can become pregnant, talk with your doctor about your birth control needs while you’re using Tukysa.

For women using Tukysa

Women who are sexually active and able to become pregnant should use birth control while taking Tukysa. And they should continue to use birth control for at least 1 week after stopping Tukysa.

For men using Tukysa

Men who are sexually active with a partner who could become pregnant should use birth control while taking Tukysa. And they should continue using birth control for at least 1 week after stopping Tukysa.

It’s not known if Tukysa passes into breast milk, or if it can affect how your body makes breast milk.

However, it’s recommended that you don’t breastfeed while you’re taking Tukysa. And you should continue to avoid breastfeeding for at least 1 week after you stop taking this drug.

If you’re currently breastfeeding, talk with your doctor about the safety of using Tukysa. They’ll help you decide if you should either continue breastfeeding or start taking Tukysa.

Here are answers to some frequently asked questions about Tukysa.

Is Tukysa a chemotherapy drug?

No, Tukysa isn’t a chemotherapy drug. (Chemotherapy describes traditional drugs used to treat cancer.) Chemotherapy drugs kill all the cells in your body that are rapidly multiplying (making more cells). So chemotherapy can kill some healthy cells along with cancer cells.

Instead, Tukysa is a targeted therapy drug. These therapies act more precisely on cancer cells than chemotherapy drugs do. Targeted therapy drugs work by blocking specific proteins in cancer cells. These proteins make the cancer cells multiply more rapidly than healthy cells do.

Specifically, Tukysa blocks the action of a protein called HER2. HER2 stands for human epidermal growth factor receptor 2. This protein is present in large amounts in HER2-positive (HER2+) breast cancer. It’s responsible for the rapid growth and spread of this type of cancer.

But keep in mind that Tukysa is approved for use in combination with a chemotherapy drug called capecitabine (Xeloda).

In addition, it’s also approved for use with another targeted therapy called trastuzumab (Herceptin). Like Tukysa, Herceptin also targets the HER2 protein. But it does so in a different way than Tukysa does.

These three drugs work together to attack cancer cells from several different angles. In this way, they can help treat advanced forms of HER2+ breast cancer.

Will Tukysa cure my cancer?

No, unfortunately, there’s currently no known cure for cancer. However, taking Tukysa could help you to live longer without your cancer getting worse or spreading further.

To learn more about Tukysa’s effectiveness, see the section “Tukysa uses” above.

Can men with breast cancer take Tukysa?

Yes, Tukysa is approved for use in both men and women with certain forms of HER2-positive (HER2+) breast cancer. For information about this condition, see the section “Tukysa uses” above.

For more information about breast cancer in men, see this article.

Will I need to have lab tests done while I’m using Tukysa?

Yes. You’ll need to have blood tests to monitor the health of your liver while you’re taking Tukysa. This monitoring is done because Tukysa can sometimes damage the liver.

The blood tests you’ll have done are called liver function tests (LFTs). They measure the levels of certain substances that can be released into your blood if you have liver damage. Examples of these substances include:

You’ll typically have LFTs done every 3 weeks while you’re taking Tukysa. Your doctor will also likely order LFTs if you have any symptoms of liver problems. To learn more about possible symptoms of liver issues, see the section “Tukysa side effects” above.

Also, keep in mind that Tukysa is used with two other drugs for breast cancer treatment: capecitabine (Xeloda) and trastuzumab (Herceptin). So during Tukysa treatment, you’ll also have certain lab tests done to check for side effects of these other drugs.

And your doctor will also order various tests to check to see if the treatment regimen is working for your cancer.

If you have questions about the lab tests you’ll need to have done while you’re using Tukysa, talk with your doctor.

Is Tukysa safe for older people to take?

Yes, in general, it’s safe for older people to take Tukysa. However, older people may be more likely to have certain side effects from the drug.

In clinical studies, serious side effects occurred in 34% of people ages 65 years and over. In comparison, serious side effects occurred in 24% of people under the age of 65 years. These serious side effects included severe diarrhea, nausea, and vomiting.

There weren’t enough people ages 75 years and over in the study to know whether side effects were more common in this age group.

If you have questions about the safety of using Tukysa given your age, talk with your doctor.

Can I use Tukysa if I have liver or kidney problems?

It depends how severe the problems are. If you have mild or moderate issues with your liver or kidneys, it’s usually fine to take Tukysa.

However, if you have severe kidney problems, Tukysa isn’t recommended for you. This is because Tukysa is used in combination with capecitabine (Xeloda) to treat breast cancer. And Xeloda can’t be used by people with severe kidney problems.

It’s important to note that Tukysa is cleared from your body by your liver. So if you have severe liver problems, Tukysa can build up inside your body. This could raise your risk of side effects from Tukysa. And keep in mind that Tukysa itself can also cause severe liver damage.

While you’re taking Tukysa, you’ll have blood tests often to check the health of your liver. If you have severe liver problems, your doctor will prescribe for you a dosage of Tukysa that’s lower than usual. If your liver function gets worse while you’re taking Tukysa, your doctor may lower your dosage of the drug. Or they may have you stop treatment with Tukysa, either temporarily or permanently.

Before taking Tukysa, talk with your doctor about your health history. Tukysa may not be right for you if you have certain medical conditions or other factors affecting your health. These include:

  • Liver problems. Tukysa is cleared from your body by your liver. If you have severe liver problems, Tukysa can build up inside your body. This could raise your risk of side effects from the drug. In addition, Tukysa can cause severe liver damage. While you’re taking Tukysa, you’ll have frequent blood tests to check your liver function. If you have severe liver problems, your doctor will prescribe for you a dosage of Tukysa that’s lower than usual. If your liver function gets worse while you’re taking Tukysa, your doctor may lower your dosage of the drug. Or they may have you stop Tukysa treatment, either temporarily or permanently.
  • Pregnancy. Tukysa can cause fetal harm if it’s taken during pregnancy. For more information, please see the “Tukysa and pregnancy” section above.
  • Breastfeeding. You shouldn’t breastfeed while taking Tukysa. For more information, please see the “Tukysa and breastfeeding” section above.

Note: For more information about the potential negative effects of Tukysa, see the section “Tukysa side effects” above.

Do not use more Tukysa than your doctor recommends. For some drugs, doing so may lead to unwanted side effects or overdose.

What to do in case you take too much Tukysa

If you think you’ve taken too much of this drug, call your doctor. You can also call the American Association of Poison Control Centers at 800-222-1222 or use their online tool. But if your symptoms are severe, call 911 or go to the nearest emergency room right away.

When you get Tukysa from the pharmacy, the pharmacist will add an expiration date to the label on the bottle. This date is typically 1 year from the date they dispensed the medication.

The expiration date helps guarantee that the medication is effective during this time. The current stance of the Food and Drug Administration (FDA) is to avoid using expired medications. If you have unused medication that has gone past the expiration date, talk to your pharmacist about whether you might still be able to use it.

Storage

How long a medication remains good can depend on many factors, including how and where you store the medication.

Tukysa tablets should be stored at room temperature (68°F to 77°F/20°C to 25°C).

Keep Tukysa tablets in their original container. Don’t transfer them to another bottle. And be sure to securely replace the lid after taking a dose. Avoid storing this medication in areas where it could get damp or wet, such as in bathrooms.

Tukysa tablets will keep for 3 months after you’ve opened a new bottle of tablets. To help keep track of this time frame, write the date you opened the bottle on its label. If there are any tablets left in the bottle 3 months after you opened it, you should safely dispose of them. See below for information on disposing of this drug.

Disposal

If you no longer need to take Tukysa and have leftover medication, it’s important to dispose of it safely. This helps prevent others, including children and pets, from taking the drug by accident. It also helps keep the drug from harming the environment.

This article provides several useful tips on medication disposal. You can also ask your pharmacist for information on how to dispose of your medication.

The following information is provided for clinicians and other healthcare professionals.

Indications

Tukysa is approved to treat HER2-positive (HER2+) breast cancer that is either locally advanced and unresectable or metastatic, including cases with brain metastases. Tukysa can be prescribed for people who have been treated in the past with at least one other anti-HER2 treatment for metastatic breast cancer. Tukysa is approved for use in adult women and men.

Administration

Tukysa is taken orally twice a day.

Mechanism of action

Tukysa is a targeted therapy for HER2+ breast cancer. This aggressive form of breast cancer results from overexpression of human epidermal growth factor receptor 2 (HER2) receptors on breast cells.

The HER2 receptor has tyrosine kinase activity that activates various signaling pathways inside breast cells, causing them to grow and divide.

Tukysa binds to HER2 and inhibits its tyrosine kinase activity by blocking phosphorylation. This blocks the signaling pathways that lead to cell growth and division. In this way, Tukysa slows growth and spread of HER2+ breast cancers.

Tukysa has an additive anti-tumor effect when used with the chemotherapy drug capecitabine (Xeloda) and the HER2-targeted therapy drug trastuzumab (Herceptin).

Although it is also a targeted treatment for HER2, Herceptin works differently than Tukysa does. Herceptin blocks the HER2 receptor and prevents it from receiving growth promoting signals. Herceptin also flags HER2+ cells for destruction by the immune system.

Pharmacokinetics and metabolism

Tucatinib is rapidly absorbed after oral administration of Tukysa, taking an average of 2 hours to reach peak plasma concentration. Taking Tukysa with food does not have a significant effect on its absorption. Tucatinib takes approximately 4 days to reach steady state, and it is 97.1% bound to plasma proteins.

Tucatinib is mainly metabolized by CYP2C8, with a smaller amount metabolized by CYP3A4. The metabolites are excreted in the feces, along with approximately 16% of the administered dose as unchanged tucatinib.

Tucatinib has an average half-life of 8.5 hours.

Contraindications

There are no contraindications to Tukysa use. However, certain treatment-related toxicities may require Tukysa to be discontinued permanently.

Storage

Store Tukysa in its original bottle at room temperature (68°F to 77°F/20°C to 25°C). Dispose of any remaining tablets once the bottle has been opened for 3 months.

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 other 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.