Dazublys 150 mg Powder for concentrate for solution for infusion

Patient Leaflet Updated 24-Sep-2026 | CuraTeQ Biologics s.r.o

Dazublys 150 mg powder for concentrate for solution for infusion

PACKAGE LEAFLET: INFORMATION FOR THE USER

Dazublys 150 mg powder for concentrate for solution for infusion

Trastuzumab

▼ This medicine is subject to additional monitoring. This will allow quick identification of new safety information. You can help by reporting any side effects you may get. See the end of section 4 for how to report side effects.

Read all of this leaflet carefully before you start using this medicine because it contains important information for you.
  • Keep this leaflet. You may need to read it again.
  • If you have any further questions, ask your doctor or pharmacist.
  • If you get any side effects, talk to your doctor, pharmacist, or nurse. This includes any possible side effects not listed in this leaflet. See section 4.

In this leaflet:

1. What is Dazublys, and what it is used for
2. What you need to know before you are given Dazublys
3. How Dazublys is given
4. Possible side effects
5. How to store Dazublys
6. Contents of the pack and other information

1. What is Dazublys, and what it is used for

Dazublys 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 trastuzumab binds to HER2, it stops the growth of such cells and causes them to die.

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

  • You have early breast cancer with high levels of a protein called HER2. Trastuzumab may be prescribed with adjuvant chemotherapy with doxorubicin and cyclophosphamide in combination with paclitaxel or docetaxel or with adjuvant chemotherapy consisting of docetaxel and carboplatin.
  • You have metastatic breast cancer (breast cancer that has spread beyond the original tumor) with high levels of HER2. Trastuzumab may be prescribed in combination with the chemotherapy medicine paclitaxel or docetaxel as the 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 in 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.

2. What you need to know before you are given Dazublys
Do not use Dazublys 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 Dazublys 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 Dazublys. 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 Dazublys treatment.

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

  • you have had heart failure, coronary artery disease, heart valve disease (heart murmurs), high blood pressure, taking 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 Dazublys.
  • you suffer from breathlessness, especially if you are currently using a taxane. Dazublys 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 Dazublys.
  • you have ever had any other treatment for cancer.

If you receive Dazublys 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

Dazublys is not recommended for anyone under the age of 18 years.

Other medicines and Dazublys

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 Dazublys to be removed from the body. Therefore, you should tell your doctor, pharmacist, or nurse that you have had Dazublys if you start any new medicine within seven 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 Dazublys and for at least seven months after treatment has ended.
  • Your doctor will advise you of the risks and benefits of taking Dazublys 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 trastuzumab. This condition may be harmful to your baby in the womb and has been associated with the lungs not developing fully, resulting in fetal death.

Breast-feeding

Do not breastfeed your baby during Dazublys therapy and for seven months after the last dose of Dazublys, as this medication may pass to your baby through your breast milk. Ask your doctor or pharmacist for advice before taking any medicine.

Driving and using machines

Dazublys 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.

Sodium

Dazublys contains less than 1 mmol of sodium (23 mg) per dose, that is to say essentially sodium-free.

Polysorbate 20

This medicine contains 0.6 mg of polysorbate 20 in each 150 mg/vial (21 mg/mL) which is equivalent to 0.6 mg/60 kg/7.4 mL. Polysorbates may cause allergic reactions. Tell your doctor if you have any known allergies.

3. How Dazublys is given

Before starting the treatment, your doctor will determine the amount of HER2 in your tumor. Only patients with a large amount of HER2 will be treated with Dazublys. Dazublys 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 Dazublys depends on your body weight.

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.

Dazublys is given as an infusion into a vein (intravenous infusion, drip); this intravenous formulation is not for subcutaneous use and should be given as an intravenous infusion only.

In order to prevent medication errors, it is important to check the vial labels to ensure that the medicine is prepared and given is Dazublys (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, Dazublys is given every three weeks. Dazublys may also be given once a week for metastatic breast cancer.

If you stop using Dazublys

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 Dazublys 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 about the use of this medicine, ask your doctor, pharmacist, or nurse.

4. Possible side effects

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

During a Dazublys 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 heartbeat), 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 healthcare 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 Dazublys, 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, and palpitations (heart fluttering or irregular heartbeat) (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 Dazublys has finished, you should see your doctor and tell them that you have previously been treated with Dazublys.

Very common side effects of Trastuzumab: 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 Trastuzumab: may affect up to 1 in 10 people

  • allergic reactions
  • throat infections
  • bladder and skin infections
  • inflammation of the breast
  • inflammation of the liver
  • kidney disorders
  • increased muscle tone or tension (hypertonia)
  • pain in the arms and/or legs
  • itchy rash
  • sleepiness (somnolence)
  • haemorrhoids
  • itchiness
  • dry mouth and skin
  • dry eyes
  • sweating
  • feeling weak and unwell
  • anxiety
  • depression
  • asthma
  • infection of the lungs
  • lung disorders
  • back pain
  • neck pain
  • bone pain
  • acne
  • leg cramps

Uncommon side effects of Trastuzumab: may affect up to 1 in 100 people:

  • deafness
  • bumpy rash
  • wheezing
  • inflammation or scarring of the lungs

Rare side effects of Trastuzumab: may affect up to 1 in 1000 people

  • jaundice
  • anaphylactic reactions

Other side effects that have been reported with Trastuzumab 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 the baby in the 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 Dazublys 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. Healthcare professionals are asked to report any suspected adverse reactions (see details below). By reporting side effects you can help provide more information on the safety of this medicine.

United Kingdom

Yellow Card Scheme
Website: www.mhra.gov.uk/yellowcard

or search for MHRA Yellow Card in the Google Play or Apple App Store

5. How to store Dazublys

Dazublys 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 expiration 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 48 hours at 2 °C - 8 °C.
  • Do not use Dazublys 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 that are no longer required. These measures will help to protect the environment. Any unused medicinal product or waste material should be disposed of in accordance with local requirements.

6. Contents of the pack and other information What Dazublys contains.
  • The active substance is trastuzumab. Each vial contains 150 mg trastuzumab that has to be dissolved in 7.2 mL of water for injection. The resulting solution contains approximately 21 mg/mL of trastuzumab.
  • The other ingredient(s) are L-histidine hydrochloride monohydrate, L-histidine, α,α-trehalose dihydrate, and polysorbate 20 (E 432).
  • This medicine contains 0.6 mg of polysorbate 20 in each 150 mg /vial ( 21 mg/mL) which is equivalent to 0.6 mg/60 kg/7.4 mL. Polysorbates may cause allergic reactions. Tell your doctor if you have any known allergies.

What Trastuzumab looks like and the contents of the pack

Trastuzumab is a powder for concentration solution for intravenous infusion, which is supplied in a glass vial with a rubber stopper containing 150 mg of trastuzumab. The powder is a white to pale yellow pellet. Each carton contains one vial of powder.

Marketing Authorization Holder
CuraTeQ Biologics s.r.o
Trtinova 260/1
Cakovice
19600
Prague
Czech Republic

Manufacturer
APL Swift Services Malta Ltd.
HF26
Hal Far Industrial Estate
Qasam Industrijali Hal Far
Birzebbugia
BBG 3000
Malta

Distributed By:

Milpharm Limited
Ares
Odyssey Business Park
West End Road
Ruislip
Middlesex
HA4 6QD
United Kingdom

This leaflet was last revised in 10/2025

Detailed information on this medicine is available on the Medicines and Healthcare products Regulatory Agency website: https://products.mhra.gov.uk

AW-xxxx-xx

Company Contact Details
CuraTeQ Biologics s.r.o
Address

Trtinova 260/1, Cakovice, Prague, 196 00, Czech Republic

Medical Information Direct Line

+448000868524 (UK only)

Customer Care direct line

+448000868524 (UK only)

Telephone

+420220990139

Medical Information e-mail
WWW

https://curateqbio.com/