What’s the difference between tucatinib and neratinib?

• Tucatinib (Tukysa) is used to treat more advanced or metastatic HER2-positive (HER2+) breast cancer or RAS wild-type HER2-positive unresectable or metastatic colorectal cancer.
• Neratinib (Nerlynx) is used in early-stage HER2+ breast cancer to help prevent it from coming back, or for advanced or metastatic HER2+ breast cancer.
• These drugs may be used in combination with different chemotherapy medicines.

Metastatic cancer that has spread to other parts of the body, and advanced or unresectable breast cancer cannot be removed with surgery.

People with HER2+ cancers have a gene that causes their cells to make too much HER2 protein. Too much HER2 can cause cells to grow more aggressively.

HER2 breast cancer makes up about 20% of all breast cancers. HER2 is overexpressed in 3 to 5% of patients with metastatic colorectal cancer, and in about 10% of patients with RAS wild-type metastatic colorectal cancer.

What is tucatinib (Tukysa) approved for?

• Tucatinib (brand name: Tukysa) is approved by the FDA to be used with the medicines trastuzumab (Herceptin) and capecitabine (Xeloda) in adult patients with HER2-positive breast cancer, including cancer that has spread to the brain.
• It is also used in combination with trastuzumab to treat adult patients with RAS wild-type HER2-positive unresectable or metastatic colorectal cancer that has progressed following treatment with fluoropyrimidine-, oxaliplatin-, and irinotecan-based chemotherapy.
• Tucatinib is typically given after other treatments have failed. It is used when the cancer has spread in the body (metastatic) or cannot be removed with surgery (unresectable).

Tucatinib is an oral tablet taken by mouth two times a day (12 hours apart), with or without a meal. Tucatinib must be used within 3 months after you open the bottle. Throw away (discard) any unused tablets after 3 months.

You may need a dose adjustment if you have severe liver disease.

Tukysa was approved by the FDA in April 2020 and is manufactured by Seagen.

What is neratinib (Nerlynx) approved for?

Neratinib (brand name: Nerlynx) can be used in two different ways to treat HER2-positive breast cancer in adults:

• as a single agent for the treatment of early-stage HER2-positive breast cancer, after treatment with trastuzumab (Herceptin)-based therapy. This can help to lower the risk of recurrence.
• in combination with capecitabine (Xeloda) to treat HER2-positive breast cancer that is advanced or has spread to other parts of the body (metastatic). It is used when at least two other HER2-based breast cancer treatments are no longer effective.

Neratinib comes as an oral tablet. The dose is given once per day with food. It is given for up to one year for treatment of early breast cancer. In metastatic or advanced breast cancer, it is given until your cancer worsens or you until have intolerable side effects.

It was approved by the FDA in July 2017 and is manufactured by Puma Biotechnology.

Related questions

• When does diarrhea start when taking Nerlynx?
• Is Nerlynx (neratinib) a chemo drug?
• Can you drink alcohol with Nerlynx?

Do they have different side effects?

Tucatinib (Tukysa) and neratinib (Nerlynx) have both similar and different side effects. These side effects may occur more or less frequently in different patients, or may not occur at all.

Both tucatinib and neratinib can cause:

• diarrhea
• nausea and vomiting
• fatigue
• stomach pain
• liver toxicity
• rash
• swelling or sores in the mouth (stomatitis)
• decreased appetite

Diarrhea may be severe with the use of neratinib and your doctor will prescribe loperamide (Imodium), and possibly other medicines, to help treat the diarrhea. Follow your healthcare provider’s instructions exactly on how to use these anti-diarrheal medicines.

Tucatinib can also cause:

• headache
• anemia (lack of red-blood cells that carry oxygen throughout your body)
• redness, swelling and pain on the palms of the hand and soles of the feet
• infusion-related reactions
• fever

Neratinib can also cause:

• muscle spasms
• heartburn
• nail disorder
• dry skin
• abdominal (stomach) distention
• epistaxis (nose bleed)
• weight loss
• urinary tract infection (UTI)

This is not a full list of side effects that may occur with tucatinib and neratinib. Speak to your doctor for further information about the side effects you may expect.

• Tucatinib (Tukysa) side effects (in detail)
• Neratinib (Nerlynx) side effects (in detail)

How are tucatinib and neratinib similar?

Both tucatinib and neratinib are both:

• in a class of medicine known as HER2 inhibitors and are considered targeted-drug therapy for the treatment of breast cancer. Neratinib is not approved for use in colorectal cancer, but tucatinib is.
• used to interfere with the growth and spread of cancer cells in advanced or metastatic HER2+ breast cancer. They both inhibit HER2, a gene that can play a role in the development of breast cancer.
• given as oral tablets by mouth.
• only for use in adults. It is NOT known if either drug is safe and effective in children.
• only available as brand name products. No generic option is available for either drug yet.

Both tucatinib and neratinib are toxic during pregnancy and can cause harm to an unborn child. You will need to use effective birth control during treatment and for a period of time after your treatment ends. It is not known if these drug pass into breast milk.

You should also not breastfeed during treatment and for a certain period of time after treatment ends. Your doctor will provide more information about pregnancy and breastfeeding.

Learn more: Comparing Nerlynx vs Tukysa

This is not all the information you need to know about tucatinib (Tukysa) and neratinib (Nerlynx) for safe and effective use and does not take the place of talking to your doctor about your treatment. Review the full product information here, and discuss this information and any questions you have with your doctor or other health care provider.