tucatinib at a glance
Medicine class
Selective HER2 tyrosine kinase inhibitor
Usual role
Part of combination treatment for previously treated advanced HER2-positive breast cancer
Food
May be taken with or without food
Tablet handling
Swallow whole; do not chew, crush or split
Key monitoring
Liver tests, diarrhoea, hydration and treatment interactions
What is tucatinib used for?
The selected UK product is licensed only as part of combination therapy.
Treatment of adults with HER2-positive locally advanced or metastatic breast cancer after at least two previous anti-HER2 treatment regimens, alongside trastuzumab and capecitabine.
How does tucatinib work?
HER2 can send signals that promote cancer-cell growth. Tucatinib selectively inhibits the HER2 tyrosine kinase, reducing HER2 and HER3 signalling, cell proliferation and survival in HER2-driven tumour cells.
tucatinib preparations and strengths
Tablet
Route: Oral
Strengths: 50 mg, 150 mg
How to take tucatinib
Follow the oncology team's treatment plan. Tablets may be taken with or without food and at the same time as capecitabine.
Swallow tablets whole with water.
Do not chew, crush or split the tablets.
Do not change or stop treatment without discussing it with the oncology team.
If vomiting occurs after a tablet, do not repeat it; take the next tablet at its scheduled time.
tucatinib side effects
Common or expected effects
- Diarrhoea
- Nausea or vomiting
- Sore mouth or mouth ulcers
- Rash
- Joint pain
- Nosebleeds
- Weight loss
- Raised liver enzymes or bilirubin on blood tests
Get urgent medical advice
- Severe or persistent diarrhoea, particularly with dehydration, fever, nausea or vomiting
- Symptoms suggesting liver injury, including jaundice, dark urine or upper-right abdominal pain
- Marked weakness, dizziness, fainting, confusion or reduced urination associated with fluid loss
tucatinib in pregnancy
Human pregnancy data are lacking, and animal studies indicate potential harm to the fetus. Pregnancy status should be checked before treatment; effective contraception is required during treatment and for at least one week afterwards for patients who could become pregnant and for male patients with partners who could become pregnant. Contact the oncology team promptly if pregnancy occurs or is planned, without stopping prescribed treatment independently.
tucatinib while breastfeeding
It is unknown whether tucatinib enters human milk, and risk to an infant cannot be excluded. Breastfeeding should stop during treatment and may resume one week after treatment has ended; discuss plans with the specialist team.
tucatinib interactions
Tucatinib is affected by metabolic enzyme inducers and inhibitors and can raise concentrations of several other medicines. Check prescribed, non-prescribed and herbal products before treatment.
Rifampicin, phenytoin, carbamazepine or St John's wort
These enzyme inducers can reduce tucatinib exposure and should be avoided.
Gemfibrozil and other strong CYP2C8 inhibitors
These can substantially increase tucatinib exposure and toxicity risk; avoid concurrent use.
Sensitive CYP3A substrates, including tacrolimus, simvastatin and midazolam
Tucatinib can increase their concentrations; high-risk combinations require specialist review and may need avoidance.
Common questions about tucatinib
Answers are fully visible for fast scanning and source review.
What type of treatment is tucatinib?
It is an oral targeted anti-cancer treatment called a selective HER2 tyrosine kinase inhibitor.
Is tucatinib used on its own?
No. Its UK licence specifies use with trastuzumab and capecitabine.
Can tablets be taken with food?
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.