What is Tukysa™ (tucatinib)?

Tukysa® (tucatinib) is a drug approved by the U.S. Food and Drug Administration (FDA) for some types of breast cancer.

It is used together with trastuzumab and Xeloda® (capecitabine) to treat HER2 positive breast cancer that has been previously treated with at least one other therapy that targets HER2, and is either1:

  • Metastatic (breast cancer that has spread to other parts of the body like the liver, bones, or brain), or
  • Advanced and cannot be surgically removed. Advanced breast cancer may have spread to tissue near the breast but not to other parts of the body away from the breast.

What is HER2 status?

Breast cancer can be classified as HER2+ or HER2-. HER2 is a protein that helps cells grow. When found in high amounts in breast cancer cells, HER2 can contribute to increased cancer cell growth and potential spread. All breast cancers are generally tested for HER2 status.2

  • HER2+ tumors have a lot of HER2 protein
  • HER2- tumors have little or normal amounts of HER2 protein

What are the ingredients in Tukysa?

The active ingredient in Tukysa is tucatinib.

How does Tukysa work?

Tukysa is a type of targeted therapy. Targeted therapy drugs work on specific changes in cancer cells that are involved in the cancer cell’s growth processes. Targeted therapy drugs work differently than chemotherapy drugs, though some of the side effects may be similar. Targeted therapy drugs can get to almost anywhere in the body. This helps them treat cancers that have spread throughout the body. HER2-positive breast cancers usually grow and spread more aggressively, so researchers have developed drugs to target the HER2 protein. Targeted therapy drugs that target the HER2 protein work on HER2+ tumors but not HER2- tumors.2,3

HER2 is a kinase. Kinases are proteins that tell the cells to grow. Kinase inhibitors are drugs that block kinases. Tukysa is a kinase inhibitor, also called a tyrosine kinase inhibitor. It helps the cancer stop growing and spreading.3

What are the possible side effects of Tukysa?

Common side effects of Tukysa include1:

  • Nausea
  • Vomiting
  • Diarrhea
  • Fatigue
  • Liver problems
  • Mouth sores
  • Loss of appetite
  • Stomach pain
  • Headache
  • Hand-foot syndrome (redness, pain, swelling on the palms of hands and/or soles of feet)
  • Rash
  • Anemia (low amounts of red blood cells)

Some people who take Tukysa may experience more severe side effects. Tukysa can cause diarrhea. If you have diarrhea, tell your doctor right away. Diarrhea can become severe, causing dehydration, low blood pressure, and serious kidney problems.1

Tukysa can cause liver problems. Your doctor will order lab work to check how well your liver is working before taking Tukysa, and then every 3 weeks while you take Tukysa (may be checked additional times based on your individual situation). Tell your doctor if you have dark urine, yellowing skin or eyes, or if you bruise or bleed more frequently than usual.1

These are not all the possible side effects of Tukysa. Talk to your doctor about what to expect or if you experience any changes that worry you.

Things to know about Tukysa

Tell your doctor if you are pregnant or planning to become pregnant. Tukysa can harm an unborn baby. While taking Tukysa, men with female partners who can become pregnant and women who can become pregnant should both use effective contraceptives during treatment and for a period of time after completing treatment. Talk with your doctor about the right birth control methods for you and your partner, and how long you need to use them. If you are breastfeeding or planning to do so, talk to your doctor. You will decide with your doctor if you should take Tukysa or breastfeed, but you should not do both.1

Certain drugs interact with Tukysa. Before starting Tukysa, tell your doctor about all your health conditions, as well as any other drugs, vitamins, or supplements you are taking. This includes over-the-counter drugs.

For more information, read the full prescribing information of Tukysa.

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Written by: Editorial Team | Last reviewed: November 2020