Tucatinib

Generic name: tucatinib
Brand name: Tukysa
Dosage form: oral tablet
Drug class: HER2 inhibitors

Medically reviewed by Philip Thornton, DipPharm. Last updated on Apr 4, 2023.

What is tucatinib?

Tucatinib is a type of targeted anticancer drug, which is used in combination with other medications for the treatment of advanced breast cancer. Tucatinib belongs to a class of drugs called tyrosine kinase inhibitors.

Tucatinib targets HER2 (human epidermal growth factor receptor 2) tyrosine kinase. HER2 receptors are involved in the growth and repair of normal breast cells. But, 10 to 20 percent of breast cancers have a faulty HER2 gene, which makes too many copies of itself. This results in HER2 protein overexpression - too many HER2 receptors on the breast cells - which makes the breast cells grow and divided uncontrollably.

Tucatinib works by blocking the activity of HER2, which helps to slow the growth and spread of cancer cells. It is used in combination with trastuzumab and capecitabine because the combination helps patients live longer without their cancer progressing and survive for longer overall.

It was approved by the US Food and Drug Administration (FDA) in 2020.

What is tucatinib used for?

Tucatinib is a prescription medicine used with the medicines trastuzumab and capecitabine to treat adults with:

• human epidermal growth factor receptor-2 (HER2) positive breast cancer that has spread to other parts of the body such as the brain (metastatic), or that cannot be removed by surgery, and
• who have received one or more anti-HER2 breast cancer treatments.

It is not known if tucatinib is safe and effective in children.

Important information

Tucatinib is used with the medicines trastuzumab (Herceptin) and capecitabine (Xeloda). Also read the patient information that may come with these medicines.

What should I tell my doctor before taking tucatinib?

Before taking tucatinib, tell your healthcare provider about all of your medical conditions, including if you have liver problems.

Related/similar drugs

Kisqali, Ibrance, Trodelvy, Opdivo, Keytruda, capecitabine, Arimidex

How should I take tucatinib?

• Take tucatinib exactly as your healthcare provider tells you.
• Tucatinib is used with the medicines trastuzumab and capecitabine. Your healthcare provider will tell you the dose of trastuzumab and capecitabine you will take and how you will receive them.
• Take tucatinib 2 times a day, with or without a meal.
• Take tucatinib about 12 hours apart or at the same times every day.
• Swallow tucatinib tablets whole. Do not chew, crush, or split tucatinib tablets before swallowing. Do not take tucatinib tablets if they are broken, cracked, or damaged.

What happens if I miss a dose?

If you vomit or miss a dose of tucatinib, take your next dose at your regular time.

Dosing information

The recommended dosage of tucatinib is 300 mg taken orally twice daily with or without food. For patients with severe hepatic impairment, the recommended dosage is 200 mg orally twice daily.

See full prescribing information for additional information about tucatinib dosing.

What are the side effects of tucatinib?

Tucatinib may cause serious side effects, including:

• Diarrhea. Diarrhea is common with tucatinib and can sometimes be severe. Tell your healthcare provider if you have a change in your bowel movements or severe diarrhea. Severe diarrhea can lead to loss of too much body fluids (dehydration), low blood pressure, kidney problems and death. Your healthcare provider may prescribe medicines to treat your diarrhea during treatment with tucatinib.
• Liver Problems. Tucatinib can cause severe liver problems. Your healthcare provider will do blood tests to check your liver function before and every 3 weeks during treatment with tucatinib, or as needed. Tell your healthcare provider right away if you have any signs and symptoms of liver problems including:
  • itching
  • yellowing of your skin or eyes
  • dark or brown urine (tea-colored)
  • pain in the upper right side of your stomach-area (abdomen)
  • feel very tired
  • decreased appetite
  • bleeding or bruising more easily than normal

The most common side effects of tucatinib:

• diarrhea
• rash, redness, pain, swelling or blisters on the palms of your hands or soles of your feet
• nausea
• tiredness
• increased liver function blood tests
• vomiting
• mouth sores (stomatitis)
• decreased appetite
• stomach-area (abdomen) pain
• headache
• low red blood cell counts (anemia)
• rash

Your healthcare provider may change your dose of tucatinib, temporarily stop, or permanently stop treatment with tucatinib if you have certain side effects.

Tucatinib may cause fertility problems in males and females, which may affect the ability to have children. Talk to your healthcare provider if you have concerns about fertility.

These are not all of the possible side effects of tucatinib. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Interactions

Tell your healthcare provider about all the medicines you take, including prescription and over-the-counter medicines, vitamins, and herbal supplements. Tucatinib may affect the way your other medicines work, and other medicines may affect the way tucatinib works.

Know the medicines you take. Keep a list of all the medicines you take and show it to your healthcare provider and pharmacist every time you get a new medicine.

Pregnancy and breastfeeding

Tell your doctor if you are pregnant or plan to become pregnant. Tucatinib can harm your unborn baby.

Females who are able to become pregnant:

• Your healthcare provider will do a pregnancy test before you start treatment with tucatinib.
• You should use effective birth control (contraception) during treatment with tucatinib and for at least 1 week after the last dose of tucatinib. Talk with your healthcare provider about forms of birth control that you can use during this time.
• Tell your healthcare provider right away if you become pregnant or think you may be pregnant during treatment with tucatinib.

Males with female partner who are able to become pregnant should use effective birth control during treatment with tucatinib and for at least 1 week after the last dose of tucatinib.

Tell your doctor if you are breastfeeding or plan to breastfeed. It is not known if tucatinib passes into your breast milk. Do not breastfeed during treatment with tucatinib and for at least 1 week after the last dose of tucatinib.

Storage

• Store tucatinib at room temperature 68°F to 77°F (20ºC to 25ºC).
• Keep tucatinib in its original container. The tucatinib bottle contains a desiccant packet to help keep your tablets dry (protect from moisture). Keep the desiccant in the bottle.
• Tightly close the bottle of tucatinib after you take your dose.
• Tucatinib must be used within 3 months after opening the bottle. Throw away (discard) any unused tablets 3 months after opening the bottle.

Keep tucatinib and all medicines out of reach of children.

What are the ingredients in tucatinib?

Active ingredient: tucatinib

Inactive ingredients:

Tablet core: copovidone, crospovidone, sodium chloride, potassium chloride, sodium bicarbonate, colloidal silicon dioxide, magnesium stearate, and microcrystalline cellulose.

Tablet coating: yellow film coat: polyvinyl alcohol, titanium dioxide, macrogol/polyethylene glycol, talc, and yellow iron oxide non-irradiated.

Tucatinib is manufacture under the brand name Tukysa for Seagen Inc., Bothell, WA 98021.

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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