Tucaxen 50

Indications

Tucatinib is used together with Trastuzumab and Capecitabine to treat adults with HER2 positive breast cancer that has spread (metastatic) or cannot be removed by surgery, including cancer that has spread to the brain, after previous HER2 targeted treatment. It may also be used with Trastuzumab for certain HER2 positive bowel (colorectal) cancers, as decided by the cancer specialist.

How It Works

Tucatinib is a targeted cancer medicine called a tyrosine kinase inhibitor. It blocks HER2, a protein on some cancer cells that sends signals telling the cells to grow and divide. Blocking HER2 slows or stops the growth of these cancer cells. It can reach the brain, which helps in cancer that has spread there.

Dosage and Administration

Tucatinib tablets are taken by mouth twice a day, about 12 hours apart, with or without food, as prescribed by your cancer specialist. Swallow tablets whole. The dose may be reduced or paused if side effects occur. Do not change the dose yourself.

Interactions

• Strong CYP2C8 inhibitors such as Gemfibrozil must be avoided, as they greatly increase tucatinib levels.
• Strong enzyme inducers such as Rifampicin, Carbamazepine, Phenytoin and St John's Wort reduce its effect.
• Tucatinib raises levels of medicines broken down by CYP3A, such as Midazolam, some statins, Tacrolimus and Ciclosporin.
• It may raise Digoxin levels.
• Tell your doctor about all medicines and herbal products you use.

Contraindications

Allergy to Tucatinib or any ingredient of the tablets.

Side Effects

Common side effects are diarrhoea, hand foot syndrome (redness, swelling and pain of the palms and soles, also caused by capecitabine), nausea, vomiting, tiredness, mouth sores, reduced appetite, weight loss, rash, headache, nose bleeds, raised liver enzymes and raised creatinine on blood tests.

Get urgent medical help if you have severe or persistent diarrhoea (more than 4 extra loose stools a day, or with dizziness or fainting), yellowing of the skin or eyes, dark urine, severe tiredness with pain in the upper right abdomen, or signs of a severe allergic reaction.

Pregnancy and Lactation

Tucatinib can harm an unborn baby. Women who could become pregnant should have a pregnancy test before starting and use effective contraception during treatment and for at least 1 week after the last dose; male patients with female partners should also use contraception for at least 1 week after. Do not breastfeed during treatment and for at least 1 week after the last dose.

Precautions and Warnings

• Liver blood tests are checked before starting and regularly during treatment.
• Start anti diarrhoea treatment and drink plenty of fluids at the first sign of diarrhoea, as advised by your team.
• Raised creatinine may occur without true kidney damage; your doctor will interpret blood tests.
• Tell your doctor about any liver problems before starting.

Overdose

There is limited experience with overdose. Contact your doctor or go to hospital immediately if too many tablets are taken.

Therapeutic Class

Antineoplastic, HER2 tyrosine kinase inhibitor.

Storage

Store below 30°C in the original container with the desiccant, in a dry place away from light and out of the reach of children.