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Trade/other name(s): Campath, Campath 1-H

Why would this drug be used?

This drug is used to treat chronic lymphocytic leukemia, and is being studied for use against other leukemias, lymphomas, and blood disorders. It may also be helpful in organ and blood stem cell transplants.

How does this drug work?

Alemtuzumab is a type of drug known as a monoclonal antibody. A monoclonal antibody is a man-made version of an immune system protein that fits like a lock and key with a certain receptor protein.

Alemtuzumab attaches to the CD52 protein (antigen) found on both normal and cancerous B and T cell lymphocytes (white blood cells) as well as other immune cells. Once it attaches to that protein on those cells, it brings in other immune cells to help kill them (those cells).

Before taking this medicine

Tell your doctor…

  • If you are allergic to anything, including medicines, dyes, additives, or foods.
  • If you have any medical conditions such as kidney disease, liver disease (including hepatitis), heart disease, congestive heart failure, diabetes, gout, or infections. These conditions may require that your medicine dose, regimen, or timing be changed.
  • If you are pregnant, trying to get pregnant, or if there is any chance of pregnancy. This drug may cause problems if either the male or female is taking it at the time of conception or during pregnancy. Men and women who are taking this drug should use some kind of birth control during and for at least 6 months after treatment. Check with your doctor about what kinds of birth control can be used with this medicine.
  • If you are breast-feeding. This drug may pass into breast milk and affect the baby. Breast-feeding should be stopped during treatment and for at least 3 months afterward.
  • If you think you might want to have children in the future. It is not known whether or not this drug can affect fertility. Talk with your doctor about the possible risk with this drug and the options that may preserve your ability to have children.
  • About any other prescription or over-the-counter medicines you are taking, including vitamins and herbs. In fact, keeping a written list of each of these medicines (including the doses of each and when you take them) with you in case of emergency may help prevent complications if you get sick.

Interactions with other drugs

Any drugs or supplements that interfere with blood clotting can raise the risk of bleeding during treatment with alemtuzumab. These include:

  • vitamin E
  • non-steroidal anti-inflammatory drugs (NSAIDs) such as aspirin, ibuprofen (Advil, Motrin), naproxen (Aleve, Naprosyn), and many others
  • warfarin (Coumadin)
  • ticlopidine (Ticlid)
  • clopidogrel (Plavix)

Note that many cold, flu, fever, and headache remedies contain aspirin or ibuprofen. Ask your pharmacist if you aren't sure what is in the medicines you take.

No serious interactions with other drugs are known at this time. But this does not necessarily mean that none exist. Check with your doctor, nurse, or pharmacist about your other medicines, herbs, and supplements, and whether alcohol can cause problems with this medicine.

Interactions with foods

No serious interactions with food are known at this time. Check with your doctor, nurse, or pharmacist about whether some foods may be a problem.

Tell all the doctors, dentists, nurses, and pharmacists you visit that you are taking this drug.

How is this drug taken or given?

Alemtuzumab is given as an infusion into a vein. The treatment is usually given over 2 hours, but the first few infusions may take longer (up to 6 hours) until your doctor knows how you react to the medicine. At the start of treatment, infusions are given each day. The dose depends upon your size, whether other medicines are given with it, and your blood counts. A lower dose is given at first, and slowly increased over the next 3 to 7 days. Once the standard dose is reached, treatment is given 3 times a week (usually Monday, Wednesday, and Friday) for up to 12 weeks.

If you have a break in treatment of 7 days or more, you will need to be started on a smaller dose again, and the dose increased over a few days. People can react to the infusion (see "Precautions"), so you may be given medicines before this drug to help prevent a reaction. You will also get some medicines to take at home to help prevent certain infections during and for a few weeks after this treatment is completed.


This drug can cause allergic reactions in some people when the drug is given, especially during and right after the first treatment. Mild reactions usually consist of fever and chills. More serious reactions happen rarely, but can be dangerous. Symptoms can include feeling lightheaded or dizzy (due to low blood pressure and shock), fever or chills, hives, nausea, itching, headache, coughing, shortness of breath, chest pain, tightness in the throat, or swelling of the face, tongue, or eyes. Tell your doctor or nurse right away if you notice any of these symptoms during or after getting the drug.

Your doctor will probably test your blood before and during your treatment, looking for possible effects of the drug on blood counts (described below) or on other body organs. Based on the test results, you may be given medicines to help treat any effects. Your doctor may also need to reduce or delay your next dose of this drug, or even stop it altogether. Keep all your appointments for lab tests and doctor visits.

This drug can lower your white blood cell count. This can increase your chance of getting an infection. Be sure to let your doctor or nurse know right away if you have any signs of infection, such as fever (100.5° or higher), chills, pain when passing urine, new cough, or bringing up sputum. Your doctor may prescribe medicines for you to take during and after treatment to help prevent certain infections.

This drug may lower your platelet count in the weeks after it is given, which can increase your risk of bleeding. Speak with your doctor before taking any drugs or supplements that might affect your body’s ability to stop bleeding, such as aspirin or aspirin-containing medicines, warfarin (Coumadin), or vitamin E. Tell your doctor right away if you have unusual bruising, or bleeding such as nosebleeds, bleeding gums when you brush your teeth, vomit that is bloody or looks like coffee grounds, or black tarry stools.

This drug may lower your red blood cell count. If this occurs, it is usually a few weeks after starting treatment. A low red blood cell count (known as anemia) can cause shortness of breath, or make you to feel weak or tired all the time. Your doctor may give you medicines to help prevent or treat this condition, or you may need to get blood transfusions.

Tell all doctors and dentists who are planning surgery on you if you have received this drug in the past year. If you need blood products they will need to be radiated to prevent a complication called graft versus host disease.

Do not get any immunizations (vaccines), either during or after treatment with this drug, without your doctor's OK. Alemtuzumab may affect your immune system. This could make vaccinations ineffective, or even lead to serious infections if you get live vaccines during treatment or for some time afterward. Try to avoid contact with people who have recently received a live virus vaccine, such as the oral polio vaccine or smallpox vaccine. Check with your doctor about this.

Both men and women should avoid conceiving a child during and for at least 6 months after treatment in order to prevent harm to the fetus. Talk with your doctor about what kind of birth control you can use with this medicine.

Possible side effects

You will probably not have most of the following side effects, but if you have any talk to your doctor or nurse. They can help you understand the side effects and cope with them.


  • mild allergic reaction with first few infusions (may include fever, headache, chills, itching, hives, nausea)*
  • low white blood cell count, which can last 6-12 months, with increased risk of infection*
  • low platelet count with increased risk of bleeding*
  • low red blood cell count*
  • fever
  • nausea
  • vomiting

Less common

  • allergic reaction with later infusions (same symptoms as above)
  • abdominal pain, back pain, or chest pain
  • headache
  • feeling tired
  • infections, which can be serious*
  • diarrhea
  • mouth sores
  • loss of appetite
  • shortness of breath
  • trouble sleeping
  • anxiety
  • cough
  • itching
  • rash
  • blood pressure changes
  • swelling in the hands or feet
  • abnormal blood test results which suggest that the drug is affecting the liver or kidneys (Your doctor will discuss the importance of this finding.)


  • serious allergic reaction, with trouble breathing, swelling of the mouth or face, tightness in the throat, faintness, heart attack, shock, cardiac arrest*
  • serious damage to the bone marrow, so that it stops making blood cells
  • feeling dizzy
  • rapid heart rate
  • upset stomach
  • constipation
  • muscle aches
  • sore throat
  • deaths due to allergic reactions, severe bone marrow damage, infections, or other causes*

*See "Precautions" section for more detailed information.

There are other side effects not listed above that can also occur in some patients. Tell your doctor or nurse if you develop these or any other problems.

FDA approval

Yes – first approved in 2001

Disclaimer: This information does not cover all possible uses, actions, precautions, side effects, or interactions. It is not intended as medical advice, and should not be relied upon as a substitute for talking with your doctor, who is familiar with your medical needs.

Last Medical Review: 01/04/2010
Last Revised: 01/24/2013