[Durgical](https://durgical.com/en/) › [DurgiPedia](https://durgical.com/en/durgipedia/) › [Pharmacology](https://durgical.com/en/pharmacology/) › [Multiple sclerosis disease-modifying therapies](https://durgical.com/en/pharmacology/classes/multiple-sclerosis-disease-modifying-therapies/) › Alemtuzumab

# 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.

Updated Nov 1, 2026

## Quick facts

**Group**
[Multiple sclerosis disease-modifying therapies](https://durgical.com/en/pharmacology/classes/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.

On this page

- The basics Mechanism of action
- Indications
- Adverse effects
- Pharmacokinetics
- Memory aid

- Safety Contraindications
- Key interactions
- What is monitored
- Administration and safety
- Pregnancy and breastfeeding
- Nursing care

- Study Test yourself

- Connections Connections

## Mechanism of action

◆**CD52, a surface protein of lymphocytes**Alemtuzumab

ⓘ 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.

**Target in 3D:** CD52, a surface protein of lymphocytes. PDB structure 1CE1 (RCSB PDB, public domain). [View the structure at RCSB PDB](https://www.rcsb.org/structure/1CE1) · Drag to rotate · pinch to zoom

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 →](https://durgical.com/en/conditions/multiple-sclerosis/)
- Chronic lymphocytic leukaemia (a separate product and regimen) [Chronic lymphocytic leukaemia →](https://durgical.com/en/conditions/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

### Serious (rare, important)

- Autoimmune disease: low platelets (bleeding), kidney disease, thyroid over- or underactivity
- Serious infusion reactions, during the infusion and up to 3 days after
- Stroke and tears in the arteries to the brain, mostly within 3 days of a dose
- Cancers: thyroid cancer, melanoma and blood cancers
- Serious infections, including herpes and listeriosis

## 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

## Memory aid

«ALEMtuzumab = ALL-ELIMINATING Me-cells»: it empties the lymphocytes, then watch for autoimmunity for 4 years.

## 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.

[Add to my cards (3)](https://durgical.app/estudiar/?add=/en/pharmacology/alemtuzumab/)

[More Pharmacology questions →](https://durgical.com/en/practice/?f=pharmacology)

## Connections

## Related drugs 3

- [Natalizumab](https://durgical.com/en/pharmacology/natalizumab/)
- [Ocrelizumab](https://durgical.com/en/pharmacology/ocrelizumab/)
- [Fingolimod](https://durgical.com/en/pharmacology/fingolimod/)

## Related conditions 2

- [Multiple sclerosis](https://durgical.com/en/conditions/multiple-sclerosis/)
- [Chronic lymphocytic leukaemia](https://durgical.com/en/conditions/chronic-lymphocytic-leukaemia/)

[← Back to the class: Multiple sclerosis disease-modifying therapies](https://durgical.com/en/pharmacology/classes/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](https://medlineplus.gov/druginfo/meds/a619012.html) (MedlinePlus (U.S. National Library of Medicine), 2026); [ATCDDD - ATC/DDD Index](https://atcddd.fhi.no/atc_ddd_index/?code=L04AG06) (WHO Collaborating Centre for Drug Statistics Methodology, 2026).

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Representative model, for educational purposes only.

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Source: https://durgical.com/en/pharmacology/alemtuzumab/
License: CC BY 4.0 (https://creativecommons.org/licenses/by/4.0/). Cite as: DurgiPedia (durgical.com), https://durgical.com/en/pharmacology/alemtuzumab/