Herzuma contains the active substance trastuzumab, which is a monoclonal antibody. Monoclonal antibodies attach to specific proteins or antigens. Trastuzumab is designed to bind selectively to an antigen called human epidermal growth factor receptor 2 (HER2). HER2 is found in large amounts on the surface of some cancer cells where it stimulates their growth. When Herzuma binds to HER2 it stops the growth of such cells and causes them to die.

Your doctor may prescribe Herzuma for the treatment of breast and gastric cancer when:

• You have early breast cancer, with high levels of a protein called HER2.
• You have metastatic breast cancer (breast cancer that has spread beyond the original tumour) with high levels of HER2. Herzuma may be prescribed in combination with the chemotherapy medicine paclitaxel or docetaxel as first treatment for metastatic breast cancer or it may be prescribed alone if other treatments have proved unsuccessful. It is also used in combination with medicines called aromatase inhibitors with patients with high levels of HER2 and hormone receptor-positive metastatic breast cancer (cancer that is sensitive to the presence of female sex hormones).
• You have metastatic gastric cancer with high levels of HER2, when it is in combination with the other cancer medicines capecitabine or 5-fluorouracil and cisplatin.

Do not use Herzuma if

• You are allergic to trastuzumab, to murine (mouse) proteins or any of the other ingredients of this medicine (listed in section 6).
• You have severe breathing problems at rest due to your cancer or if you need oxygen treatment.

Warnings and precautions
Your doctor will closely supervise your therapy.

Heart checks
Treatment with Herzuma alone or with a taxane may affect the heart, especially if you have ever used an anthracycline (taxanes and anthracyclines are two other kinds of medicine used to treat cancer). The effects may be moderate to severe and could cause death. Therefore, your heart function will be checked before, during (every three months) and after (up to two to five years) treatment with Herzuma. If you develop any signs of heart failure (inadequate pumping of blood by the heart), your heart function may be checked more frequently (every six to eight weeks), you may receive treatment for heart failure or you may have to stop Herzuma treatment.

Talk to your doctor, pharmacist or nurse before you are given Herzuma if:

• You have had heart failure, coronary artery disease, heart valve disease (heart murmurs), high blood pressure, taken any high blood pressure medicine or are currently taking any high blood pressure medicine.
• You have ever had or are currently using a medicine called doxorubicin or epirubicin (medicines used to treat cancer). These medicines (or any other anthracyclines) can damage heart muscle and increase the risk of heart problems with trastuzumab.
• You suffer from breathlessness, especially if you are currently using a taxane. Trastuzumab can cause breathing difficulties, especially when it is first given. This could be more serious if you are already breathless. Very rarely, patients with severe breathing difficulties before treatment have died when they were given trastuzumab.
• You have ever had any other treatment for cancer.

If you receive Herzuma with any other medicine to treat cancer, such as paclitaxel, docetaxel, an aromatase inhibitor, capecitabine, 5-fluorouracil, or cisplatin you should also read the patient information leaflets for these products.

Children and adolescents
Herzuma is not recommended for anyone under the age of 18 years.

Other medicines and Herzuma
Tell your doctor, pharmacist or nurse if you are taking, have recently taken or may take any other medicines.

It may take up to 7 months for Herzuma to be removed from the body. Therefore, you should tell your doctor, pharmacist or nurse that you have had Herzuma if you start any new medicine in the 7 months after stopping treatment.

Pregnancy  

• If you are pregnant, think you may be pregnant or are planning to have a baby, ask your doctor, pharmacist or nurse for advice before taking this medicine.
• You should use effective contraception during treatment with Herzuma and for at least 7 months after treatment has ended.
• Your doctor will advise you of the risks and benefits of taking Herzuma during pregnancy. In rare cases, a reduction in the amount of (amniotic) fluid that surrounds the developing baby within the womb has been observed in pregnant women receiving Herzuma. This condition may be harmful to your baby in the womb and has been associated with the lungs not developing fully resulting in foetal death.

Breast-feeding
Do not breast-feed your baby during Herzuma therapy and for 7 months after the last dose of Herzuma, as Herzuma may pass to your baby through your breast milk.

Ask your doctor or pharmacist for advice before taking any medicine.

Driving and using machines
Herzuma may affect your ability to drive a car or operate machines. If during treatment you experience symptoms, such as dizziness, sleepiness, chills or fever, you should not drive or use machines until these symptoms disappear.

Before starting the treatment your doctor will determine the amount of HER2 in your tumour. Only patients with a large amount of HER2 will be treated with Herzuma. Herzuma should only be given by a doctor or nurse. Your doctor will prescribe a dose and treatment regimen that is right for you. The dose of Herzuma depends on your body weight.

Herzuma is given as an intravenous infusion (“drip”) directly into your veins. The first dose of your treatment is given over 90 minutes and you will be observed by a health professional while it is being given in case you have any side effects. If the first dose is well tolerated the next doses may be given over 30 minutes (see section 2 under “Warnings and precautions”). The number of infusions you receive will depend on how you respond to the treatment. Your doctor will discuss this with you.

In order to prevent medication errors, it is important to check the vial labels to ensure that the medicine being prepared and given is Herzuma (trastuzumab) and not another trastuzumab-containing product (e.g. trastuzumab emtansine or trastuzumab deruxtecan).

For early breast cancer, metastatic breast cancer and metastatic gastric cancer, Herzuma is given every 3 weeks. Herzuma may also be given once a week for metastatic breast cancer.

If you stop using Herzuma
Do not stop using this medicine without talking to your doctor first. All doses should be taken at the right time every week or every three weeks (depending on your dosing schedule). This helps your medicine work as well as it can.

It may take up to 7 months for Herzuma to be removed from your body. Therefore your doctor may decide to continue to check your heart functions, even after you finish treatment.

If you have any further questions on the use of this medicine, ask your doctor, pharmacist or nurse.

Like all medicines, this medicine can cause side effects, although not everybody gets them. Some of these side effects may be serious and may lead to hospitalisation.

During a Herzuma infusion, chills, fever and other flu like symptoms may occur. These are very common (may affect more than 1 in 10 people). Other infusion-related symptoms are: feeling sick (nausea), vomiting, pain, increased muscle tension and shaking, headache, dizziness, breathing difficulties, high or low blood pressure, heart rhythm disturbances (palpitations, heart fluttering or irregular heart beat), swelling of the face and lips, rash and feeling tired. Some of these symptoms can be serious and some patients have died (see section 2 under “Warnings and precautions”).

These effects mainly occur with the first intravenous infusion (“drip” into your vein) and during the first few hours after the start of the infusion. They are usually temporary. You will be observed by a health care professional during the infusion and for at least six hours after the start of the first infusion and for two hours after the start of other infusions. If you develop a reaction, they will slow down or stop the infusion and may give you treatment to counteract the side effects. The infusion may be continued after the symptoms improve.

Occasionally, symptoms start later than six hours after the infusion begins. If this happens to you, contact your doctor immediately. Sometimes, symptoms may improve and then get worse later.

Serious side effects
Other side effects can occur at any time during treatment with Herzuma, not just related to an infusion. Tell a doctor or nurse straight away, if you notice any of the following side effects:

• Heart problems can sometimes occur during treatment and occasionally after treatment has stopped and can be serious. They include weakening of the heart muscle possibly leading to heart failure, inflammation of the lining around the heart and heart rhythm disturbances. This can lead to symptoms such as breathlessness (including breathlessness at night), cough, fluid retention (swelling) in the legs or arms, palpitations (heart fluttering or irregular heart beat) (see 2. Heart checks).

Your doctor will monitor your heart regularly during and after treatment but you should tell your doctor immediately if you notice any of the above symptoms.

• Tumour lysis syndrome (a group of metabolic complications occurring after cancer treatment characterized by high blood levels of potassium and phosphate, and low blood levels of calcium). Symptoms may include kidney problems (weakness, shortness of breath, fatigue and confusion), heart problems (fluttering of the heart or a faster or slower heartbeat), seizures, vomiting or diarrhoea and tingling in the mouth, hands or feet.

If you experience any of the above symptoms when your treatment with Herzuma has finished, you should see your doctor and tell them that you have previously been treated with Herzuma.

Other very common side effects (may affect more than 1 in 10 people):

• Infections
• Diarrhoea
• Constipation
• Heartburn (dyspepsia)
• Fatigue
• Skin rashes
• Chest pain
• Abdominal pain
•  Joint pain
• Low counts of red blood cells and white blood cells (which help fight infection) sometimes with fever
• Muscle pain
• Conjunctivitis
• Watery eyes
• Nose bleeds
• Runny nose
• Hair loss
• Tremor
• Hot flush
• Dizziness
• Nail disorders
• Weight loss
• Loss of appetite
• Inability to sleep (insomnia)
• Altered taste
• Low platelet count
• Bruising
• Numbness or tingling of the fingers and toes, which occasionally may extend to the rest of the limb
• Redness, swelling or sores in your mouth and/or throat
• Pain, swelling, redness or tingling of hands and/or feet
• Breathlessness
• Headache
• Cough
• Vomiting
• Nausea

Other common side effects (may affect up to 1 in 10 people):

• Allergic reactions
• Dry mouth and skin
• Throat infections
• Dry eyes
• Bladder and skin infections
• Sweating
• Inflammation of the breast
• Feeling weak and unwell
• Inflammation of the liver
• Anxiety
• Kidney disorders
• Depression
• Increased muscle tone or tension (hypertonia)
• Asthma
• Infection of lungs
• Pain in the arms and/or legs
• Lung disorders
• Itchy rash
• Back pain
• Sleepiness (somnolence)
• Neck pain
• Haemorrhoids
• Bone pain
• Itchiness
• Acne
• Leg cramps

Other uncommon side effects (may affect up to 1 in 100 people):

• Deafness
• Bumpy rash
• Wheezing
• Inflammation or scarring of the lungs

Other rare side effects (may affect up to 1 in 1000 people):

•  Jaundice
• Anaphylactic reactions

Other side effects with unknown frequency (frequency cannot be estimated from the available data):

• Abnormal or impaired blood clotting
• High potassium levels
• Swelling or bleeding at the back of the eyes
• Shock
• Abnormal heart rhythm
• Respiratory distress
• Respiratory failure
• Acute accumulation of fluid in the lungs
• Acute narrowing of the airways
• Abnormally low oxygen levels in the blood
• Difficulty in breathing when lying flat
• Liver damage
• Swelling of the face, lips and throat
• Kidney failure
• Abnormally low levels of fluid around baby in womb
• Failure of the lungs of the baby to develop in the womb
• Abnormal development of the kidneys of the baby in the womb

Some of the side effects you experience may be due to your underlying cancer. If you receive Herzuma in combination with chemotherapy, some of them may also be due to the chemotherapy.

If you get any side effects, talk to your doctor, pharmacist or nurse.

Keep this medicine out of the sight and reach of children.

Store in a refrigerator (2-8°C).

Store in the original package.

Infusion solutions should be used immediately after dilution.

A vial of Herzuma aseptically reconstituted with sterile water for injections (not supplied) is chemically and physically stable for 7 days at 2-8^oC after reconstitution and must not be frozen.

After aseptic dilution in polyvinylchloride, polyethylene or polypropylene bags containing 9 mg/ml (0.9%) sodium chloride solution for injection, chemical and physical stability of Herzuma has been demonstrated for up to 30 days at 2-8°C, and 24 hours at temperatures not exceeding 30°C.

From a microbiological point of view, the reconstituted solution and Herzuma infusion solution should be used immediately. If not used immediately, in-use storage times and conditions prior to use are the responsibility of the user, and would not normally be longer than 24 hours at 2°C to 8°C, unless reconstitution and dilution have taken place under controlled and validated aseptic conditions.

Do not use this medicine after the expiry date which is stated on the package after “EXP”. The expiry date refers to the last day of that month.

Do not use Herzuma if you notice any particulate matter or discoloration prior to administration.

Do not throw away any medicines via wastewater or household waste. Ask your pharmacist how to throw away medicines you no longer use. These measures will help protect the environment.