Alemtuzumab
Multiple sclerosis disease-modifying therapies
Multiple sclerosis disease-modifying therapies
An anti-CD52 antibody that wipes out circulating lymphocytes for a long time. Given by IV infusion in yearly courses for active MS.
Quick facts
- Group
- Multiple sclerosis disease-modifying therapies
- Target
- CD52, a surface protein of lymphocytes
- Used for
- Relapsing forms of multiple sclerosis
- Key effects
- Infusion reactions · Insomnia · Mouth or throat pain
- Monitor
- Laboratory tests every month · Yearly skin examination
- ATC
- L04AG06
No doses: the clinician sets them by the current guideline.
Mechanism of action
The figure shows the Fab fragment of alemtuzumab, an anti-CD52 antibody, bound to a synthetic peptide that mimics its antigen; the drug is the antibody itself, so there is no small ligand.
Alemtuzumab is a humanized monoclonal antibody against CD52, a protein on B and T lymphocytes and on other immune cells. Binding to CD52 triggers antibody-dependent lysis of these cells and a profound lymphocyte depletion that can last more than a year. As the immune system rebuilds, MS activity falls, but autoimmune diseases can appear.
- Alemtuzumab binds CD52 on lymphocytes
- The cells are destroyed (antibody-dependent lysis)
- Lymphocytes stay low for months
- The rebuilt immune system attacks myelin less
Indications
- Relapsing forms of multiple sclerosis, usually after other treatments have not worked well Multiple sclerosis →
- Chronic lymphocytic leukaemia (a separate product and regimen) Chronic lymphocytic leukaemia →
Adverse effects
Common
- Infusion reactions: rash, flushing, headache, fever
- Insomnia
- Tingling or burning skin, itch
- Mouth or throat pain
- Hair loss and taste changes
Contraindications
- HIV infection
- Active serious infection
- Hypersensitivity to alemtuzumab
Key interactions
- Live vaccines
- Not given during treatment without the treating team's advice; vaccines are reviewed before starting
- Other immunosuppressants
- Additive immunosuppression and infection risk
What is monitored
- Laboratory tests every month, continuing for 4 years after the last dose
- Symptoms of thyroid over- or underactivity
- Yearly skin examination
- Yearly cervical screening in women
Administration and safety
- Intravenous infusion over several hours in a clinic or hospital, on consecutive days, with a second course a year later
- The patient stays at the centre at least 2 hours after each infusion
- In some countries it is given only through a restricted safety programme
Pregnancy and breastfeeding
Pregnancy is avoided during treatment and for 4 months after the last course; a pregnancy test may be needed before starting.
Nursing care
- Monitor vital signs and watch for infusion reactions during and after the infusion
- Teach the stroke signs: facial droop, sudden severe headache, neck pain, weakness on one side
- Explain the long monitoring plan and why every blood test matters
- Advise avoiding listeria-risk foods (deli meats, soft cheeses, unpasteurized milk) before and during treatment
Pharmacokinetics
- Absorption
- Intravenous infusion only
- Elimination
- The effect lasts far longer than the drug: lymphocytes recover over many months
Test yourself
Think of the answer, then tap the question to see it.
What is the target of alemtuzumab?
CD52 on lymphocytes and other immune cells.
Which two autoimmune complications of alemtuzumab are most typical?
Immune thrombocytopenia and kidney disease (also thyroid disease).
How long is laboratory monitoring continued after the last course of alemtuzumab?
Monthly for 4 years after the last dose.
Connections
← Back to the class: Multiple sclerosis disease-modifying therapies
Educational content on how drugs work; not a prescribing guide and no substitute for a health professional's advice. No doses are given.
Sources: Alemtuzumab Injection (Multiple Sclerosis): MedlinePlus Drug Information (MedlinePlus (U.S. National Library of Medicine), 2026); ATCDDD - ATC/DDD Index (WHO Collaborating Centre for Drug Statistics Methodology, 2026).
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Representative model, for educational purposes only.