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

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

LEQEMBI contains the active substance lecanemab. Lecanemab is a monoclonal antibody. Antibodies are found naturally in our blood and help us to fight infection. Monoclonal antibody therapies mimic natural antibodies but are made in a laboratory. They work by binding to a target protein to reduce the harmful effect of that protein. Lecanemab binds to a protein called amyloid beta, which is involved in Alzheimer’s disease.

LEQEMBI is used to treat the early stages of Alzheimer’s disease in adults who carry one copy of a gene called apolipoprotein E4, also known as ApoE4, or in adults who do not carry this gene.

Your healthcare provider will perform testing to make sure that LEQEMBI is right for you.

Alzheimer’s disease is an illness that affects the brain. Communications between brain cells become blocked due to amyloid beta plaques. This eventually leads to problems with memory, thinking and behaviour. Alzheimer’s disease symptoms can be different for everyone. Symptoms usually develop slowly and get worse over time, becoming severe enough to interfere with daily tasks.

In Alzheimer’s disease, clumps of amyloid beta protein form plaques in the brain. LEQEMBI works by binding to these clumps and reducing them. This slows down progression of early Alzheimer’s disease.

• If you are allergic to lecanemab or any of the other ingredients of this medicine (listed in section 6).
• If your Magnetic Resonance Imaging (MRI) brain scan shows small spots of bleeding or fluid in the brain, or evidence of larger bleeding in the past.
• If you are receiving medicines (called anticoagulants) to prevent blood clots.

Talk to your doctor, pharmacist or nurse before you are given LEQEMBI if any of the following apply to you:

• you have had a mini stroke, stroke or seizure (fit) within the last 12 months.
• you have a bleeding disorder.
• you have Down syndrome.

Allergic reactions

Tell your doctor or nurse straight away if you develop any signs or symptoms of an allergic reaction during or after you are given LEQEMBI. See section 4 “Possible side effects” for signs of an allergic reaction.

Amyloid related imaging abnormalities (ARIA)

LEQEMBI can cause a side effect called amyloid related imaging abnormalities, or “ARIA”. ARIA is a side effect that does not usually cause any symptoms, but serious symptoms, including life-threatening symptoms can occur. ARIA is most commonly seen as temporary swelling in one or more areas of the brain (ARIA-E) that usually resolves over time. Some people may also have small spots of bleeding in or on the surface of the brain (ARIA-H), and infrequently, larger areas of bleeding in the brain can occur. Most people with ARIA do not get symptoms, however some people may have symptoms, such as:

• Headache
• Confusion
• Dizziness
• Vision changes
• Feeling sick (nausea)
• Difficulty walking
• Fits (seizures)

Tell your doctor or nurse if you experience any of these symptoms.

ARIA-E and ARIA-H are visible on a Magnetic Resonance Imaging (MRI) brain scan. The MRI uses magnetic waves to create detailed images of the soft tissues of the body. Your doctor will do MRI scans before and during your treatment with LEQEMBI to check you for ARIA.

Genetic Risk Factors for ARIA

Some people carry a gene called ApoE4 that increases the risk for ARIA, particularly in people that have 2 copies of the gene (homozygous ApoE4 carriers). Your doctor will discuss this with you and arrange a genetic test to make sure that LEQEMBI is suitable for you.

Infusion-related reactions

Infusion-related reactions are a very common side effect of LEQEMBI treatment. Tell your doctor or nurse straight away if you experience any symptoms associated with your LEQEMBI infusion. For symptoms, see section 4 “Possible side effects”. Most infusion-related reactions occur during the infusion or within 2.5 hours after the infusion is completed. If you have an infusion-related reaction, you may be given medicines before your infusions to decrease your chance of having an infusion-related reaction. These medicines may include antihistamines, paracetamol, anti-inflammatory medicines or steroids.

Medicines used to prevent or dissolve blood clots

The risk of having a larger bleed in the brain (known as intracerebral haemorrhage) with LEQEMBI treatment is increased in patients receiving medicines used to prevent blood clots (anticoagulants) or to dissolve them (thrombolytic agents). Tell your doctor that you are being treated with LEQEMBI before you receive any medication to prevent blood clots or dissolve them. LEQEMBI can be used together with aspirin and other medicines that prevent your blood cells sticking together (antiplatelet agents).

LEQEMBI is not for use in children and adolescents aged less than 18 years because Alzheimer’s disease does not occur in this age group.

Tell your doctor or pharmacist if you are taking, have recently taken or might take any other medicines. In particular tell your doctor:

• If you are taking medicines (called anticoagulants) that prevent blood clots. LEQEMBI should not be used with these medicines.

LEQEMBI can be used alone, or together with other medicines that treat symptoms of Alzheimer’s disease.

If you are pregnant or breast-feeding, think you may be pregnant or are planning to have a baby, ask your doctor for advice before you are given this medicine. It is not known if LEQEMBI will harm your unborn baby or if this medicine passes into breast milk.

If you become pregnant while you are using LEQEMBI, tell your doctor. You and your doctor can discuss if you should carry on with treatment.

If you are breast-feeding, you and your doctor can discuss if you should carry on with breast-feeding or treatment.

Your doctor should advise you about using contraception during treatment with LEQEMBI and up to 3 months after the last dose of LEQEMBI.

Some patients may experience symptoms such as dizziness or confusion. This could affect the ability to drive and use machines. Do not drive or use tools or machinery until you feel better.

The recommended dose is 10 milligrams per kilogram of your body weight (mg/kg). It should be given to you every 2 weeks.

Your doctor will arrange MRI scans before your fifth, seventh and fourteenth doses of LEQEMBI. This is routine monitoring to check if you have ARIA. Additional scans can be performed at other times during treatment if your doctor thinks you need them.

Your doctor may pause or stop treatment, depending on your MRI results.

If you miss an infusion of LEQEMBI, talk to your doctor to arrange to have it as soon as possible. Do not wait until your next planned infusion.

Your doctor may recommend pausing or stopping treatment, depending on your clinical test results.

Immediately tell the healthcare professional giving you LEQEMBI if you notice any signs of an allergic reaction while or shortly after you are given this medicine. Signs of an allergic reaction include swelling of the face, lips, mouth or tongue, hives or difficulty breathing.

Uncommon side effects (may affect up to 1 in 100 people)

• Areas of larger bleeds in the brain (known as intracerebral haemorrhages).

Very common side effects (may affect more than 1 in 10 people)

• Small spots of bleeding in or on the surface of the brain (ARIA-H) (see section 2 “What you need to know before you are given LEQEMBI” for more information on ARIA-H).
• Infusion-related reactions. Signs include fever, flu-like symptoms such as chills, body aches, feeling shaky and joint pain, feeling sick (nausea), being sick (vomiting), dizziness or light-headedness, changes in your heart rate or feeling like your chest is pounding, difficulty breathing or shortness of breath.
• Headache.

Common side effects (may affect up to 1 in 10 people)

• Swelling in areas of the brain (ARIA-E) (see section 2 “What you need to know before you are given LEQEMBI” for more information on ARIA-E).
• Abnormal heart rhythm (atrial fibrillation). Signs of this can include irregular heartbeat (racing or fluttering in your chest), chest pain, shortness of breath, dizziness or feeling faint, tiredness, or finding it harder to exercise.
• Rash.

Talk to your doctor about how to manage these side effects.

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

• The active substance is lecanemab. Each mL of concentrate contains 100 mg lecanemab.
• The other ingredients are histidine hydrochloride monohydrate, arginine hydrochloride, polysorbate 80, and water for injections.

LEQEMBI is a clear to slightly opalescent and colourless to pale yellow concentrate for solution for infusion that comes in a glass vial.

LEQEMBI is available in packs containing 1 vial.

1 vial packs

These contain either 2 mL or 5 mL.

Company Contact Address: For further information on your medicine contact Medical Information at Eisai Europe Limited in Hatfield. Tel: + 44 (0) 208 600 1400