• Keep this leaflet. You may need to read it again.
• If you have any further questions, ask your doctor or nurse.
• If you get any side effects, talk to your doctor or nurse. This includes any possible side effects not listed in this leaflet. See section 4.

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

Loncastuximab tesirine consist of 2 parts; an antibody (a type of protein designed to recognise and attach to a specific target) and a cytotoxic agent (a medicine able to kill cells, including cancer cells). The antibody in this medicine is designed to attach to CD19, a protein that is found on the surface of B-cells. When the antibody binds to these cells, including the cancer cells, the medicine enters the cells and kills them.

Talk to your doctor or nurse before you are given Zynlonta if you:

• have an active infection or have had one recently
• have liver problems; symptoms may include skin and eyes appearing yellowish (jaundice). Your doctor will monitor you for side effects during treatment.
• are pregnant or plan to become pregnant.
• Zynlonta can harm your unborn baby (see section “Pregnancy and breast-feeding and fertility” for further information).

Tell your doctor or nurse straight away if you have any of the following serious side effects.

Infections

Serious infections, including infections that can cause death, have occurred in people treated with Zynlonta. Tell your doctor or nurse straight away if you have new or worsening signs or symptoms of infection, which are listed in section 4, under ‘Serious side effects’.

Fluid retention

Your body may hold too much fluid during treatment with Zynlonta. This can be serious. Tell your doctor or nurse straight away if you have any signs or symptoms of fluid retention, which are listed in section 4, under ‘Serious side effects’. Your doctor will give appropriate treatment for the fluid retention. If you have serious swelling your doctor may stop treatment until the swelling goes down.

Low blood cell counts (platelets, red blood cells, and white blood cells)

Low levels of certain blood cells (low blood cell counts) can be serious or severe. Your doctor or nurse will monitor your blood cell counts during treatment with Zynlonta. Tell your doctor or nurse straight away if you have any signs and symptoms of infection, which are listed in section 4, under ‘Serious side effects’. Low blood cell counts could be responsible for your infection.

Skin reactions

Serious skin reactions have occurred in people treated with Zynlonta. Exposure to sunlight (including through glass or car windows) may cause severe sunburn. It is important to wear sunscreen and appropriate clothing to ensure you do not burn. Tell your doctor or nurse straight away if you get new or worsening severe skin reactions. Signs and symptoms are listed in section 4, under ‘Possible side effects’.

This medicine should not be given to children or young people under the age of 18. This is because there is no information about its use in this age group.

Tell your doctor if you are taking, have recently taken or might take any other medicines.

Women of child-bearing potential must use effective contraception during treatment with Zynlonta, and for 10 months after the last dose. Men with partners of child-bearing potential must use effective contraception during treatment with Zynlonta, and for 7 months after the last dose.

Talk to your doctor about effective contraception.

You should avoid getting pregnant if you are taking this medicine. Tell your doctor immediately if you become pregnant or think that you are pregnant during treatment with Zynlonta. Your doctor may do a pregnancy test before starting treatment with Zynlonta.

Do not breast-feed during treatment, and for 3 months after the last dose. It is not known if Zynlonta passes into breast milk.

Zynlonta may cause fertility problems in men, which may affect their ability to father children. You can seek advice on how to preserve sperm before starting treatment. Talk to your doctor for more information.

Zynlonta has no or negligible influence on your ability to drive and use machines. If you get infusion-related reactions or if you feel tired, weak or dizzy (see section 4) do not drive, cycle or use tools or machines until you feel better.

See section 4 for more information about side effects.

During your treatment with Zynlonta you will also be given another medicine called dexamethasone to help reduce side effects as a result of treatment.

You will be given 4 mg of dexamethasone either by mouth or into your vein twice a day for three days, beginning the day before you receive Zynlonta treatment.

If you do not receive dexamethasone the day before your treatment, then it must be given at least 2 hours before you are given Zynlonta.

Zynlonta is usually given every 3 weeks (on day 1 of a 21-day cycle).

• Your doctor will give you medicines before each infusion to lower your chance of side effects.
• Your doctor may stop your treatment, delay your treatment, or change your dose of Zynlonta if you have severe side effects (see section 4 possible side effects).
• Your doctor will do regular blood tests to check for side effects of Zynlonta.
• Your doctor will decide how many treatment cycles you need.

Since the infusion is given to you by your doctor or other appropriately trained staff, an overdose is unlikely. If you inadvertently receive too much medicine, your doctor will monitor you and give you additional treatment as required.

If you miss a dose of Zynlonta, it should be given as soon as possible. You might need to reschedule receiving the next planned dose to ensure that it is given 21 days after the missed dose. The 21-day interval between doses should be maintained.

You should not stop the therapy early without talking with your doctor first.

The therapy for lymphoma with Zynlonta usually requires a number of infusions. The number of infusions that you receive will depend on how you are responding to treatment. Therefore, even if you see your symptoms improve, you should continue to take Zynlonta until your doctor decides that your medicine should be stopped. If the treatment is stopped too early, your symptoms may return.

Infections

Serious infections, including infections that can cause death, have occurred in people treated with Zynlonta. Tell your doctor or nurse straight away if you notice any of the following signs and symptoms:

• fever
• chills
• flu-like symptoms (cough, tiredness or weakness, and body aches)
• severe headache
• cuts or scrapes that are red, warm, swollen, or painful

Fluid retention

Your body may hold too much fluid during treatment with Zynlonta. This can be serious. You can get swelling in various parts of your body including your hands, feet (very common) and abdomen (common), or around internal organs such as your heart (common) and lungs (very common).

Tell your doctor or nurse straight away if you notice any of the following signs and symptoms:

• have chest pain (common)
• difficulty breathing (very common)
• swelling in any part of your body (very common)

Low blood cell counts

Low blood cell counts (very common) can be serious or severe. Your doctor or nurse will monitor your blood counts during treatment with Zynlonta. Tell your doctor or nurse straight away if you notice any bruising or bleeding, or any of the signs and symptoms of infections above.

Skin reactions

Skin reactions (common) have occurred in people treated with Zynlonta. Some of these can be serious. Tell your doctor or nurse straight away if you get new or worsening severe skin reactions, including:

• sensitivity to sunlight including sunburn-like reactions such as skin peeling and irritation following exposure to light
• itchy rash
• blistering of skin
• darker skin patches
• irritation, swelling, pain, and/or skin damage at the injection site.

Tell your doctor or nurse if you notice any of the following side effects:

Very common: may affect more than 1 in 10 people

• tiredness and pale skin
• abnormal blood tests showing:
  • low levels of neutrophils, a type of white blood cell that fight infection, sometimes with fever
  • low blood platelet count which can lead to bleeding and bruising
  • liver problems
• loss of appetite
• feeling sick or vomiting
• diarrhoea
• stomach pain
• constipation
• reddening of the skin
• rash
• itching.

Common: may affect up to 1 in 10 people

• infection of the lungs including bronchitis or pneumonia
• nose and throat infection
• rash characterised by a flat, red area on the skin that is covered with small, raised bumps
• muscle pain
• joint pain
• back and neck pain
• pain in the arms and legs
• lack of energy.

Uncommon: may affect less than 1 in 100 people

• pus filled raised bumps on the skin
• limb discomfort
• muscle and bone discomfort
• inflammation of the membrane around the heart.

Not known: frequency cannot be estimated from the available data

• spider veins (broken blood vessels located near surface of skin)
• blisters
• rash consisting of tiny-to-small fluid-filled blisters

If you get any side effects, talk to your doctor or pharmacist. This includes any possible side effects not listed in this leaflet. You can also report side effects directly via the Yellow Card Scheme. Website www.mhra.gov.uk/yellowcard or search for MHRA Yellow Card in the Google Play or Apple App Store. By reporting side effects you can help provide more information on the safety of this medicine.

• The active substance is loncastuximab tesirine. Each vial contains 10 mg of loncastuximab tesirine. After reconstitution, each mL contains 5 mg of loncastuximab tesirine.
• The other ingredients are: L-histidine, L-histidine monohydrochloride, polysorbate 20, sucrose.

This medicine is a white to off-white powder, which has a cake-like appearance. It comes in a glass vial and is for single use only. The powder needs to be reconstituted and diluted before infusion.

Each pack contains 1 vial.