Trastuzumab emtansine is a targeted therapy used to treat certain HER2-positive breast cancers that have spread or come back. They can also be used to treat other types of cancer as part of a clinical trial.

WHAT IS TRASTUZUMAB EMTANSINE?

Trastuzumab emtansine is made up of two different drugs joined together into one. Trastuzumab is a monoclonal antibody that works by targeting specific proteins (receptors) on the surface of cells. The other drug, emtansine, is a chemotherapy drug that causes damage to cancer cells.

Trastuzumab emtansine is not the same thing as trastuzumab. We have separate information on trastuzumab.

HOW DOES TRASTUZUMAB EMTANSINE WORK?

Some breast cancers have a protein called human epidermal growth factor receptor 2 (HER2) on the surface of their cells. These are known as HER2-positve breast cancers. The extra HER2 receptors help the cancer cells to divide and grow.

Trastuzumab emtansine latches on to the HER2 protein and blocks the receptor. This prevents the cells from dividing and growing. It also releases the chemotherapy drug directly into the cancer cell, damaging and destroying it from within the cell.

WHEN IS TRASTUZUMAB EMTANSINE GIVEN?

This drug may be given to treat people with HER2 breast cancer that has spread to other parts of the body or has reappeared in the same area. You need to have had previous treatment with trastuzumab and docetaxel or paclitaxel.

HOW IS TRASTUZUMAB EMTANSINE ADMINISTERED?

Trastuzumab emtansine is given in the chemotherapy day unit or during a short hospital stay. A chemotherapy nurse will give it to you.

Before the day of treatment, a nurse will take a blood sample from you to see if you are fit for the treatment. You will also be able to see a doctor or nurse before having the treatment. They will ask you how you have been feeling. If the results of your blood test are good on the day of your treatment, the pharmacist will prepare your chemotherapy.

If the results of your blood test do not go back to normal or if you have been having certain side effects, your doctor may postpone your treatment or lower the dose of trastuzumab emtansine you receive.

Your nurse will give you trastuzuma emtansine through one of the following methods:

• a short, thin tube (cannula) that a nurse inserts into a vein in your arm or hand
• a tube that goes below the skin of your chest toward a nearby vein (central line)
• a thin tube that is placed in a vein in your arm and then goes up toward a vein in the chest (PICC).

Your nurse will give you trastuzuma emtansine as a drip (infusion). They usually run the drip through a pump, giving you the treatment over a set time. The first infusion is given over 90 minutes. After this, it can be given in just 30 minutes.

WHILE YOU ARE BEING GIVEN TRASTUZUMAB EMTANSINE

Some people may have the following side effects while they are receiving the treatment:

ALLERGIC REACTION

Trastuzumab emtansine can cause an allergic reaction while it is being given. This is more common with the first treatment, which is why it is given slowly over 90 minutes. Your nurse will give you drugs to help prevent or reduce a reaction. They will monitor you during and after each treatment. If you have an allergic reaction, it will be treated quickly.

The signs of a reaction may include: flue-like symptoms (headache, high temperature, or chills), feeling flushed, dizziness or feeling out of breath, pain in the back, abdomen, or chest, or feeling unwell. Tell your nurse immediately if you have any of these symptoms.

Rarely, a reaction can happen a few hours after the treatment. If you develop any of these symptoms or feel unwell after you get home, get in touch with your hospital immediately for advice.

YOUR COURSE OF TRASTUZUMAB EMTANSINE

You will have trastuzumab emtansine as part of a course or cycle, consisting of several treatment sessions and lasting several months. Each cycle normally lasts for 3 weeks. You will get trastuzumab emtansine on the first day of the cycle. After this, you will have a 20-day rest period. After 21 days, the second treatment cycle begins.

Trastuzumab emtansine is given for as long as it keeps the cancer under control. Your doctor or nurse will tell you more about how many cycles you are likely to have.

POSSIBLE SIDE EFFECTS OF TRASTUZUMAB EMTANSINE

Each person's reaction to cancer treatment is different: while some people develop very few side effects, others may experience more. The side effects described below will not affect everyone who is treated with the drug. We have outlined only the most common.

If you notice you develop any side effects that are not listed here, talk to your doctor or specialist nurse. Your nurse will advise you on managing the side effects. After treatment, the side effects start to get better.

RISK OF INFECTION

Trastuzumab emtansine can reduce your number of white blood cells, which help fight off infection. This is more likely if you are receiving chemotherapy at the same time. This may make you more susceptible to infection. When the number of white blood cells is low, this is called neutropenia.

Contact your hospital immediately if any of the following happens:

• your temperature goes above 38 ° C
• you suddenly feel unwell, even if your temperature is normal
• you have symptoms of infection, which may include sore throat, coughing, diarrhea, or the need to urinate frequently.

The number of white blood cells normally increases gradually, returning to normal before your next chemotherapy treatment. You will have a blood test done before your next treatment. If your white blood cells are still low, your doctor may postpone the treatment for a short period of time.

BRUISING AND BLEEDING

This drug may lower the number of platelets in your blood. Platelets are cells that help the blood to clot. Tell your doctor if you have any unexplained bleeding or bruising. This includes nosebleeds, bleeding gums, blood spots, or skin eruptions (rashes).

ANEMIA (LOW RED BLOOD CELLS)

This drug may lower the number of red blood cells in your blood. Red blood cells transport oxygen throughout the body. If you have a low number of red blood cells, you may be tired and short of breath. Tell your doctor or nurse if you feel like this. If you are very anemic, you may require a drip to give you extra red blood cells (blood transfusion).

TIREDNESS

Feeling very tired is a common side effect. Fatigue is often worst toward the end of treatment and for a few months after the treatment has finished. Try to maintain a good rhythm and rest as much as you need. Help balance this with a bit of light exercise, such as short walks. If you feel drowsy, don't drive or operate heavy machinery.

NAUSEA

This may happen in the first few days after treatment, though it is normally mild. Your doctor will prescribe you antiemetic drugs. Take the medicine exactly as your nurse or pharmacist tells you.

CONSTIPATION

Trastuzumab emtansine can cause constipation and abdominal pain. Drinking at least two liters of fluids each day will help if this is the case. Try to eat more high-fiber foods such as fruit, vegetables, and whole-grain bread and get some light exercise.

DIARRHEA

If you have diarrhea, your doctor may prescribe drugs to help control it. Take these exactly as you are instructed. Make sure you drink at least two liters of fluids each day if you have diarrhea.

Rarely, diarrhea may be more serious, which is why it is important to contact the hospital. If you have more than 3 episodes of diarrhea a day, contact the hospital.

DRYNESS OF THE MOUTH

Having a dry mouth is common. Drink lots of fluids and add sauces to your food to keep it moist. Sucking on ice cubes can also help, though you shouldn't do this if you have a sore mouth or other mouth problems. If your lips are dry, use lip balm or vaseline.

SORENESS OF THE MOUTH

You may have a sore mouth or mouth ulcers. This can make you more susceptible to infection in your mouth. Lightly brush your teeth and/or dentures in the morning and night and after meals. Use a soft-bristle toothbrush. Your nurse might ask you to rinse your mouth out regularly or use mouthwash. It is important that you follow all the instructions you are given and that you drink a lot of fluids.

Tell your nurse or doctor if you have any mouth problems. They can prescribe you drugs to prevent or treat infections of the mouth and to treat any kind of pain.

SKIN CHANGES

You may develop a rash which may itch. Always tell your doctor or nurse about any change to your skin. They can advise you and prescribe creams or medication that may help. Normally, changes in the skin are temporary and get better as soon as the treatment is over.

MUSCLE AND/OR JOINT PAIN

You may have pain or cramping in your joints or muscles for a few days after the treatment. Tell your doctor if this happens so they can prescribe you some painkillers. Let them know if your pain doesn't go away.

HEADACHES

Trastuzumab emtansine can cause headaches. If this happens, tell your doctor or nurse. They can give you painkillers for this.

NUMBNESS OR TINGLING IN THE HANDS OR FEET

These symptoms are caused by the effect of the drug on the nerves. It is called peripheral neuropathy. It may also be hard for you to press buttons and it can make other tasks more uncomfortable. Always tell your doctor if you have these symptoms.

The symptoms normally get better slowly once the treatment is over, though in some people they may never go away.

PAIN AND REDNESS IN THE PALMS OF THE HANDS AND SOLES OF THE FEET

This is known as palmar-plantar syndrome or hand-foot syndrome. This is not common, and the inflammation gets better when the treatment ends. Your doctor or nurse can prescribe creams to improve the symptoms. It may help to keep your hands and feet cool and avoid wearing tight-fitting socks, shoes, and gloves.

EFFECTS ON THE NERVOUS SYSTEM

Some people have trouble sleeping, feel dizzy, off balance, or have difficulty remembering things.

Tell your doctor or nurse if you have any of these symptoms. It is important not to drive or operate machinery if you feel dizzy.

LOW LEVELS OF POTASSIUM

Trastuzumab emtansine can lower the levels of potassium you have in your blood. These changes are normally mild and return to normal after the treatment. You will have blood tests before and during the treatment to check on your potassium levels. Your doctor can prescribe potassiuim supplements if this is necessary.

EYE PROBLEMS

Your eyes may tear up, dry out, or feel sore, and your vision may turn blurry. If your eyes become red and inflamed (conjunctivitis), tell your doctor. You many need antibiotic eye drops. Always tell your doctor or nurse about any change to your vision.

HAIR LOSS

Some people may notice that their hair thins out. This will return to normal after the treatment is over.

LESS COMMON SIDE EFFECTS OF TRASTUZUMAB EMTANSINE

EFFECTS ON THE LUNGS

Trastuzumab emtansine can cause changes in the lungs. Always let your doctor know if you have wheezing, coughing, fever, or if you are out of breath. You should also get in touch with them if there is any existing problem with breathing. If necessary, tests can be done to check your lungs.

CHANGES IN THE LIVER

Trastuzumab emtansine can affect the functioning of your liver. These changes are normally mild and return to normal after the treatment. You are unlikely to notice any changes, though your doctor will check how well your liver is working by having you take regular blood tests.

CHANGES IN THE HEART

In rare cases, this drug can affect the way the heart works. You will have tests done to check on your heart during and after the treatment.

If you have pain or pressure in your chest, feel out of breath, or notice changes in your heart rate at any time during or after treatment, let your doctor know immediately. These symptoms could be caused by other conditions, but it important to have them looked at by a doctor.

The side effects can normally be controlled or improved. Always tell your doctor or nurse about any side effects you have so they can help you feel better.

ADDITIONAL INFORMATION ON TRASTUZUMAB EMTANSINE

BLOOD CLOT RISK

Cancer increases the chances of blood clot (thrombosis), and trastuzumab emtansine can make this even more likely. A blood clot may cause symptoms such as pain, reddening or swelling in a leg, difficulty breathing, and pain in the chest. Get in touch with your doctor immediately if you have any of these symptoms. A blood clot is a serious matter, but your doctor can use drugs to thin your blood.

OTHER MEDICINES

Some drugs, including those bought over the counter in a store or pharmacy, may be harmful to you while you are taking trastuzumab emtansine. Tell your doctor if you are taking any medicines, including over-the-counter drugs, complementary therapies, and herbal remedies.

FERTILITY

This treatment may affect your ability to conceive. It is important that you talk to your doctor before beginning treatment.

CONTRACEPTION

Little is known about the effects of trastuzumab emtansine on developing babies. Therefore, it is not recommendable to become pregnant while taking this drug.

It is unknown whether trastuzumab emtansine is present in semen or vaginal fluid. In order to protect your partner, it is safest to avoid having sex or use a barrier contraceptive device for about 48 hours after the chemotherapy.

BREASTFEEDING

There is a potential risk that trastuzumab emtansine may be present in breast milk, and therefore women are recommended not to breast feed during the treatment and for a few months afterward.

HOSPITAL ADMISSION

If you are admitted to the hospital for any reason not related to cancer, it is important that you tell your doctors and nurses caring for you that you are receiving treatment with trastuzumab emtansine.