Alemtuzumab

*Alemtuzumabum*

For medical students2 min readUpdated 2026-10-10

Alemtuzumab is a monoclonal antibody medication used in oncohematology and organ transplantation due to its ability to effectively deplete lymphocytes.

Antibody typeHumanized monoclonal antibodies

Molecular targetCD52 receptor on the lymphocyte surface

Duration of effectLasts up to one year

ComplicationCytokine release syndrome upon initial administration

Characteristics and Origin

In terms of its chemical structure, alemtuzumab is a humanized monoclonal antibody. This drug is specifically engineered to target certain structures of the human immune system, which determines its specific pharmacological activity.

Mechanism of Action and Pharmacokinetics

The primary target for the drug is the CD52 receptor located on lymphocytes.

By binding to its target, the drug triggers lysis (destruction) of lymphocytes.
The destroyed cells are actively cleared from the bloodstream.
The pharmacological effect is highly prolonged, lasting up to one year after administration.

Indications and Administration Regimens

Depending on the therapeutic goals, the drug is used in various regimens:

Monotherapy — indicated for chronic lymphocytic leukemia.
Combination therapy — used in organ transplantation procedures. In these cases, it is combined with agents such as glucocorticoids, tacrolimus, or sirolimus to prevent rejection.

Side Effects and Risks

Therapy with this medicinal substance carries certain risks and adverse reactions:

Cytokine release syndrome — develops predominantly during the very first administration of the drug.
Hematologic abnormalities — anemia and neutropenia are frequently observed, and pancytopenia may develop in rarer cases.

Mnemonic

AlemtuZUMab targets CD52 and causes a STORM upon initial infusion.

Frequently asked questions

What side effects are characteristic of alemtuzumab therapy?

Alemtuzumab therapy is characterized by a broad spectrum of adverse reactions, including infusion-related, hematologic, infectious, and autoimmune complications.

Key side effects include:

Infusion reactions — acute allergic reactions and "cytokine release syndrome" upon the initial administration of the drug.
Hematologic abnormalities — development of anemia, neutropenia, and, more rarely, pancytopenia.
Infections — increased risk of opportunistic infections (including listeriosis and progressive multifocal leukoencephalopathy), as well as potential reactivation of latent infections.
Autoimmune complications — thyroid disorders, immune thrombocytopenia (ITP), and other secondary autoimmune reactions.

By what route is alemtuzumab administered into the body?

Alemtuzumab is administered intravenously.

The recommended dosing regimen is 12 mg administered intravenously via infusion. The standard treatment course includes two consecutive treatment cycles: the patient receives five infusions during the first year, and three infusions are scheduled for the second year.

What autoimmune demyelinating disease is treated with alemtuzumab?

Alemtuzumab is used to treat multiple sclerosis.

The drug belongs to disease-modifying therapies (DMTs) for multiple sclerosis. Therapy requires careful monitoring: there is a prolonged period to achieve full effect over the first 18 months, and the first efficacy assessment milestone occurs at 30 months. Regular blood count monitoring and screening for the prevention of latent infection reactivation are also necessary.

What structural type of antibody is alemtuzumab?

It is a humanized monoclonal antibody.

What is the cellular target of this drug?

The target is the CD52 receptor located on lymphocytes.

Which disease is treated using alemtuzumab monotherapy?

As monotherapy, the drug is used for chronic lymphocytic leukemia.

What drugs is alemtuzumab combined with during organ transplantation?

It is combined with glucocorticoids, tacrolimus, or sirolimus.

Go deeper

Structure and production of humanized monoclonal antibodies
Physiological role of the CD52 receptor in the body
Pathogenesis of cytokine release syndrome during biological drug administration
Criteria for selecting combination therapy in organ transplantation
Management of hematologic abnormalities (anemia and neutropenia)