Herceptin 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 Herceptin binds to HER2 it stops the
growth of such cells and causes them to die.

Your doctor may prescribe Herceptin 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. Herceptin 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-flououracil and cisplatin.

Do not use Herceptin if:
 you are allergic to trastuzumab, to murine (mouse) proteins, or to 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 Herceptin 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 Herceptin. 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 Herceptin treatment.
 

Talk to your doctor, pharmacist or nurse before you are given Herceptin 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 Herceptin.
 you suffer from breathlessness., especially if you are currently using a taxane. Herceptin 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 Herceptin.
 you have ever had any other treatment for cancer.
 

If you receive Herceptin 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
Herceptin is not recommended for anyone under the age of 18 years.
 

Other medicines and Herceptin
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 Herceptin to be removed from the body. Therefore you should tell your
doctor, pharmacist or nurse that you have had Herceptin 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 Herceptin and for at least 7 months
after treatment has ended.
 Your doctor will advise you of the risks and benefits of taking Herceptin 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 Herceptin. 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 Herceptin therapy and for 7 months after the last dose of Herceptin
as Herceptin may pass to your baby through your breast milk.
Ask your doctor or pharmacist for advice before taking any medicine.
 

Driving and using machines
Herceptin 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.
 

3. How Herceptin is given
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 Herceptin. Herceptin 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
Herceptin depends on your body weight.
 

Two different types (formulations) of Herceptin exist:
• one is given as an infusion into a vein (intravenous infusion).
• the other is given as an injection under the skin (subcutaneous injection).
It is important to check the product labels to ensure that the correct formulation is being given as
prescribed. Herceptin intravenous formulation is not for subcutaneous use and should be given as an
intravenous infusion only.

Your doctor may consider switching your Herceptin intravenous treatment to Herceptin subcutaneous
treatment (and vice versa) if considered appropriate for you.

Herceptin intravenous formulation 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 Herceptin (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, Herceptin is given every 3
weeks. Herceptin may also be given once a week for metastatic breast cancer.

If you stop using Herceptin
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 Herceptin 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, Herceptin can cause side effects, although not everybody gets them. Some of these
side effects may be serious and may lead to hospitalisation.

During a Herceptin 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 Herceptin, 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 section 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 Herceptin has finished, you
should see your doctor and tell them that you have previously been treated with Herceptin.

Very common side effects of Herceptin: 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

Common side effects of Herceptin: 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
Uncommon side effects of Herceptin: may affect up to 1 in 100 people:
 deafness
 bumpy rash
 wheezing
 inflammation or scarring of the lungs
Rare side effects of Herceptin: may affect up to 1 in 1000 people
 jaundice
 anaphylactic reactions
Other side effects that have been reported with Herceptin use: 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 Herceptin
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.
 

Reporting of side effects
If you get any side effects, talk to your doctor, pharmacist or nurse. This includes any possible side effects
not listed in this leaflet. By reporting side effects you can help provide more information on the safety of
this medicine.

Herceptin will be stored by the health professionals at the hospital or clinic.

 Keep this medicine out of the sight and reach of children.
 Do not use this medicine after the expiry date which is stated on the outer carton and on the vial
label after EXP. The expiry date refers to the last day of that month.
 The unopened vial should be stored in a refrigerator (2°C – 8°C).
 Do not freeze the reconstituted solution.
 Infusion solutions should be used immediately after dilution. 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 – 8°C.
 Do not use Herceptin if you notice any particulate matter or discoloration prior to administration.
 Medicines should not be disposed of via wastewater or household waste. Ask your pharmacist how
to dispose of medicines no longer required. These measures will help to protect the environment.