Belantamab mafodotin

What are the main side-effects?

Here we describe the most common side-effects of belantamab mafodotin, these happen in more than one in ten patients receiving belantamab mafodotin. Side-effects can vary from person to person. If you have any side-effects or symptoms because of your myeloma and treatment with belantamab mafodotin, you should tell your doctor so they can help you manage them.

Eye-related side-effects

Eye-related side-effects are the most common side-effects for patients receiving belantamab mafodotin. The main way this presents is with damage to the cornea (the vital protective layer of the eye), which can lead to symptoms of dry eyes, blurred vision, less clear vision, eye irritation or pain, photophobia (sensitivity to light which can cause discomfort or pain), cataract (clouding of the lens of the eye) or sensation of having something in the eye. These side-effects can range from mild to severe.

Eye-related side-effects can usually be managed and reversed using dose modifications (i.e. pausing treatment for a time-limited period until the symptoms improve, or through lowering the dose of the treatment). This can usually be done without impacting on your treatment response. You should speak to your doctor if you have concerns.

Due to the eye-related side-effects, your doctor should arrange repeat eye-examinations with an ophthalmologist (an eye doctor) or another eye care professional to check your eyes before starting treatment, before you receive each dose of treatment and as needed for any new or worsening eye side-effect. You will also be given regular eye-drops (artificial tears) to use every day throughout your treatment. It is recommended to use those eye-drops at least four times a day to moisten your eyes.

It is important you keep your doctor informed about the eye-related side-effects right away if you notice any new or worsening eye symptom or vision change during treatment, to help you resolve them.

Infusion-related reactions

Some patients may have an allergic-like reaction when they receive an infusion of belantamab mafodotin. This usually develops within minutes or hours but may develop up to a day after treatment (i.e. 24 hours). Symptoms include flushing (a red and hot face), chills, fever, difficulty breathing, rapid heartbeat and a drop in blood pressure. You should contact your doctor or healthcare team immediately if you think you may be having a reaction.

Infections

As a result of treatment with belantamab mafodotin, you are at a higher risk of developing certain infections which can give you a high temperature (i.e. fever) and make you feel unwell. Most common infections include:

• COVID-19
• Infections of the nose, sinuses and throat (upper respiratory infections)
• Pneumonia (infection of the lung)

Common signs of pneumonia include high or low temperature, coughing (it may include yellow or green mucus) and wheezing, shortness of breath, fatigue, loss of appetite and confusion. To prevent or treat infections, your doctor might prescribe antibiotics (medicines that treat bacterial infections). In severe cases, you may also need to stay at the hospital and be given oxygen to help you breathe.

Whilst you are taking belantamab mafodotin, you should take precautions to help avoid infections. This might include increased handwashing and avoiding large, crowded places.  See our resources on infection prevention.

If you are taking belantamab mafodotin, it is important that you seek medical assistance immediately if you develop cold or flu-like symptoms, start to feel unwell and/or have a high or low temperature which is usually caused by the response of your body to an infection.

Blood changes which increase your risk of infection

A reason you are at more risk of infection whilst receiving belantamab mafodotin is due to changes in your blood and immune system which might make it more difficult for you to fight off infections.

• Low levels of white blood cells (leukopenia)
  Neutropenia and lymphopenia mean a low level of different white blood cells (called neutrophils and lymphocytes), which are important for the immune system and fighting infections. If you have a low level of white blood cells, you are more likely to develop an infection and get unwell. It might also take you a longer time to get better after an infection.

Your doctor will take your blood before and during treatment to monitor your white blood cell levels. In severe cases, G-CSF is a treatment that can be used to treat neutropenia. G-CSF stands for Granulocyte Colony-Stimulating Factor. It is a medication that stimulates cell growth and which can help the bone marrow make more neutrophils to help fight infections. It is injected under the skin (subcutaneously).

Other blood changes

• Low platelets (increased risk of bleeding)
Thrombocytopenia means you have a low platelet count. Platelets (also known as thrombocytes) play an important role in slowing or stopping bleeding (i.e. blood clotting) and healing wounds. A low number of platelets can increase your risk of bleeding.

Your doctor will check your blood (including platelet levels) before and during treatment. If you experience abnormal bruising or bleeding (e.g. from your gums, nose or after tests), you should inform your doctor. If severe, this may be managed through dose modifications. It might also be possible to use platelet transfusions, given by an infusion. Your doctor may recommend following some tips to avoid injury and bleeding.

• Low level of red blood cells (anaemia)
Anaemia means that you have a low level of red blood cells or low level of haemoglobin. Red blood cells play an important role in carrying oxygen around your body. If you have a low level of red blood cells you might have a lack of energy and feel weak, fatigued, breathless or light-headed. You may also have noticeably paler skin than normal.

Your doctor will take your blood before and during treatment to monitor your red blood cell levels. However, if you experience these symptoms at any point you should speak to your doctor. Treatment for anaemia may include iron tablets, blood transfusions (which gives you extra red blood cells) and a drug called erythropoietin (EPO). EPO can help your body make extra red blood cells.

Fatigue

Fatigue is a feeling of extreme and persistent tiredness, which may not be relieved by rest. As with all side-effects, you should tell your doctor or nurse if you are feeling fatigued.  Treating other side-effects can help relieve fatigue. For example, your fatigue may be caused by a low number of red blood cells (anaemia – see above). If this is treated, you might start to feel less tired. Your doctor might also be able to reduce the dose of certain drugs if they are a contributing factor.

Small amounts of easy exercise can also help as well as periods of rest. Planning and anticipating your daily activities can help manage your fatigue, thinking about rest periods during the day – particularly after more strenuous activities.

Liver damage

Abnormal levels of liver enzymes in the blood can mean that your liver has been inflamed or damaged from treatment with belantamab mafodotin. Your doctor will monitor those levels through blood tests. You should tell your doctor if you notice yellowing of the skin or eyes, your urine appears dark or brown, or you have pain in your stomach. If your liver enzymes are high, your doctor will explore the cause further. They may amend the dose or frequency of belantamab mafodotin to address these side-effects.

Gastrointestinal disorders

• Diarrhoea
  Diarrhoea is where someone has three or more loose stools (i.e. bowel movements) every day. Having a balanced diet can help with this symptom, as can avoiding foods that upset your stomach like fatty and spicy food and avoiding fruit juice. If you have diarrhoea, make sure you drink plenty of water each day – around 2 – 3 litres each day. Your doctor may also prescribe you medicines to help control your diarrhoea, called anti-diarrhoeals.
• Nausea
  Nausea is where someone has an unpleasant urge to vomit. If you vomit, it is very important to stay hydrated by drinking water. Try to take small sips if you are not able to keep the water down. Anti-emetics are anti-sickness drugs, which you may be prescribed to prevent or stop your nausea and sickness.
• Constipation
  Constipation is a bowel dysfunction that makes bowel movements infrequent or difficult to pass. Stools are often hard. Symptoms can include abdominal pain. Your doctor may prescribe you constipation treatment or recommend you dietary changes. Staying hydrated is important.

Neuropathy

Neuropathy is when a nerve or several nerves are damaged, leading to pain, weakness, numbness or tingling in one or more parts of your body. It can be managed by reducing the dose and/or the schedule of the treatment, using pain relievers or neuroprotective supplements which protect the brain and nervous system from damage.

Other very common side-effects (occurring in ≥ 1/10 patients) include insomnia (sleeplessness), back pain, joint pain and cough.

Questions or concerns
If you have any concerns about your treatment or symptoms, you should speak to your doctor or healthcare team immediately.