Tukysa (Tucatinib) for Breast Cancer

Tukysa (tucatinib) is a prescription medication approved by the U.S. Food and Drug Administration (FDA) to treat adults with human epidermal growth factor receptor-2 (HER2)-positive breast cancer.

How Tukysa Works and How It’s Taken

Tukysa is a type of medicine called a kinase inhibitor. It targets HER2, a protein found on some cancer cells. Tukysa blocks signals that tell these cells to grow and divide, which may help slow the growth of HER2-positive breast cancer.

Doctors prescribe Tukysa with trastuzumab and capecitabine to treat adults with HER2-positive breast cancer. It is used when the cancer cannot be removed with surgery or has spread to other parts of the body, including the brain. It is used after the individual has already received one or more anti-HER2 treatments for cancer that has spread to other parts of the body, also called metastatic disease.

Tukysa is given as a tablet by mouth, usually two times a day, about 12 hours apart. It is taken with trastuzumab and capecitabine. The tablets should be taken around the same time each day.

Swallow Tukysa tablets whole. They can be taken with or without food.

This is based on the prescribing information, but your healthcare provider may tailor your treatment plan. Always follow their guidance.

Typical Dosing for Breast Cancer

The recommended dose of Tukysa for breast cancer is 300 milligrams by mouth two times a day in combination with trastuzumab and capecitabine. Treatment usually continues until the cancer gets worse or side effects become unacceptable.

Doctors may pause treatment, lower the dose, or stop treatment if side effects are serious or too hard to manage.

Tukysa Side Effects

In clinical trials of Tukysa used with trastuzumab and capecitabine for adults with HER2-positive breast cancer that is advanced, cannot be removed with surgery, or has spread to other parts of the body, the most common side effects occurred in at least 20 percent of people taking Tukysa with trastuzumab and capecitabine.

These side effects include:

Diarrhea
Palmar-plantar erythrodysesthesia (hand-foot syndrome)
Nausea
Hepatotoxicity (liver problems)
Vomiting
Stomatitis (mouth sores)
Decreased appetite
Anemia (low hemoglobin)
Rash

Serious Side Effects and Warnings

Tukysa can cause serious side effects that may require immediate medical attention. These include:

Severe diarrhea — This can lead to dehydration, low blood pressure, kidney problems, and death.
Hepatotoxicity (liver problems) — Severe liver injury can occur during treatment.
Embryo-fetal toxicity — Tukysa can harm your baby if you are pregnant.

Get medical help right away if you think you are having a serious reaction to Tukysa.

How To Save on Tukysa

Pfizer offers the Pfizer Oncology Together program. Eligible people may be able to get help with insurance benefits, financial assistance resources, and personalized support.

To learn more, visit Pfizer Oncology Together or call 877-744-5675.

What To Know Before Taking Tukysa

Before starting Tukysa, your doctor will check your pregnancy status if you are able to become pregnant.

Tell your doctor if you have any allergies to tucatinib or any ingredients in Tukysa.

Tell your doctor about all medications you take, including prescription drugs, over-the-counter medicines, and supplements.

Tukysa is also FDA-approved to treat certain adults with metastatic colorectal cancer.

If you vomit or miss a dose of Tukysa, take your next dose at your usual scheduled time.

Tukysa can harm your baby if you are pregnant. If you are pregnant, planning to become pregnant, or breastfeeding, talk with your doctor. If you are able to become pregnant, you should use effective birth control during treatment and for one week after your last dose.

According to the prescribing information, if a male is taking Tukysa and has a female partner who can become pregnant, he should use effective birth control during treatment and for one week after his last dose. Do not breastfeed during treatment and for one week after the last dose.

Community FAQs

These answers are fact-checked by our editorial staff.

How effective is Tukysa?

In a study of people with HER2-positive unresectable or metastatic breast cancer, Tukysa used with trastuzumab and capecitabine helped delay cancer growth or spread for a median of 7.8 months, compared with 5.6 months without Tukysa. Median overall survival was 21.9 months with Tukysa, compared with 17.4 months without it. In people with brain metastases, median progression-free survival was 7.6 months with Tukysa, compared with 5.4 months without it.

Among people with measurable disease, 40.6 percent had an overall response leading to a decrease in tumor size, compared with 22.8 percent without Tukysa.