Ofatumumab (Arzerra®)

OncoLink Team
Last Modified: January 8, 2016

Pronounced: OH-fa-TUE-mue-mab
Classification: Monoclonal Antibody

About Ofatumumab

Ofatumumab is a synthetic (man made) antibody directed against a protein called CD20, found on the surface of normal and cancerous B-cells, which are part of the immune system. More than 90% of CLL cases affect the B cells, making this a good target for therapy. An antibody is a part of the immune system that "marks" things (such as germs, bacteria and, in this case, cancer cells) to be destroyed by the immune system. Once this medication attaches itself to the B cells expressing CD20, it summons the body's immune system to attack and destroy those cells.

How to Take Ofatumumab

Ofatumumab is given by intravenous (IV, into a vein) infusion. Patients receive 12 doses over 7 months (8 weekly doses, followed by 4 weeks off therapy, followed by 4 monthly doses). It may take several hours or longer to receive your first dose of ofatumumab. You will receive premedication with oral steroids, acetaminophen, and anti-histamine to prevent an infusion reaction. Depending on how you tolerate the medication, you may receive subsequent doses more quickly.

You or anyone you live with should avoid having live or live-attenuated vaccines while receiving this medication. These include oral polio, measles, nasal flu (Flumist), rotovirus, yellow fever.

Possible Side Effects of Ofatumumab

There are a number of things you can do to manage the side effects of ofatumumab. Talk to your doctor or nurse about these recommendations. They can help you decide what will work best for you. These are some of the most common side effects:

Infusion Related Side Effects

Almost half of the people who receive ofatumumab experience an infusion reaction. Symptoms of an infusion reaction include: fever, chills, low blood pressure, shortness of breath, flushing, swelling of the throat or face, abdominal or back pain, rash and itching. You will receive several medications prior to the infusion to help prevent these reactions. Reactions are most common during the first 2 infusions. Tell your infusion nurse immediately if you notice any of these symptoms, as they may need to slow or stop the infusion.

Low White Blood Cell Count (Leukopenia or Neutropenia)

White blood cells (WBC) are important for fighting infection. While receiving treatment, your WBC count can drop, putting you at a higher risk of getting an infection. You should let your doctor or nurse know right away if you have a fever (temperature greater than 100.4), sore throat or cold, shortness of breath, cough, burning with urination, or a sore that doesn't heal.

Tips to preventing infection:

  • Washing hands, both yours and your visitors, is the best way to prevent the spread of infection.
  • Avoid large crowds and people who are sick (i.e.: those who have a cold, fever or cough or live with someone with these symptoms).
  • When working in your yard, wear protective clothing including long pants and gloves.
  • Do not handle pet waste.
  • Keep all cuts or scratches clean.
  • Shower or bath daily and perform frequent mouth care.
  • Do not cut cuticles or ingrown nails. You may wear nail polish, but not fake nails.
  • Ask your doctor or nurse before scheduling dental appointments or procedures.
  • Ask your doctor or nurse before you, or someone you live with, has any vaccinations.

Low Red Blood Cell Count (Anemia)

Your red blood cells are responsible for carrying oxygen to the tissues in your body. When the red cell count is low, you may feel tired or weak. You should let your doctor or nurse know if you experience any shortness of breath, difficulty breathing or pain in your chest. If the count gets too low, you may receive a blood transfusion.

Low Platelet Count (Thrombocytopenia)

Platelets help your blood clot, so when the count is low you are at a higher risk of bleeding. Let your doctor or nurse know if you have any excess bruising or bleeding, including nose bleeds, bleeding gums or blood in your urine or stool. If the platelet count becomes too low, you may receive a transfusion of platelets.

  • Do not use a razor (an electric razor is fine).
  • Avoid contact sports and activities that can result in injury or bleeding.
  • Do not take aspirin (salicylic acid), non-steroidal, anti-inflammatory medications (NSAIDs) such as Motrin®, Aleve®, Advil®, etc. as these can all increase the risk of bleeding. Unless your healthcare team tells you otherwise, you may take acetaminophen (Tylenol).
  • Do not floss or use toothpicks and use a soft-bristle toothbrush to brush your teeth.

Nausea and/or Vomiting

Talk to your doctor or nurse so they can prescribe medications to help you manage nausea and vomiting. In addition, dietary changes may help. Avoid things that may worsen the symptoms, such as heavy or greasy/fatty, spicy or acidic foods (lemons, tomatoes, oranges). Try antacids, (e.g. milk of magnesia, calcium tablets such as Tums), saltines, or ginger ale to lessen symptoms.

Call your doctor or nurse if you are unable to keep fluids down for more than 12 hours or if you feel lightheaded or dizzy at any time.


Your oncology team can recommend medications to relieve diarrhea. Also, try eating low-fiber, bland foods, such as white rice and boiled or baked chicken. Avoid raw fruits, vegetables, whole grain breads, cereals and seeds. Soluble fiber is found in some foods and absorbs fluid, which can help relieve diarrhea. Foods high in soluble fiber include: applesauce, bananas (ripe), canned fruit, orange sections, boiled potatoes, white rice, products made with white flour, oatmeal, cream of rice, cream of wheat, and farina. Drink 8-10 glasses on non-alcoholic, un-caffeinated fluid a day to prevent dehydration.

Skin Changes

Some patients may develop a rash, very dry or itchy skin. Use an alcohol free moisturizer on your skin and lips; avoid moisturizers with perfumes or scents. Your doctor or nurse can recommend a topical medication if itching is bothersome. If your skin does crack or bleed, be sure to keep the area clean to avoid infection. Be sure to notify your healthcare provider of any rash that develops, as this can be a reaction. They can give you more tips on caring for your skin.


Progressive Multifocal Leukoencephalopathy (PML) is a rare, but very serious, brain infection that has been reported with this medication. The signs of PML may develop over several weeks or months. They may include changes in mood or usual behavior, confusion, thinking problems, loss of memory, changes in vision, speech, or walking, and decreased strength or weakness on one side of the body. If you develop any of these signs, notify your healthcare provider immediately.

Liver Toxicity and Hepatitis B Reactivation

This medication can cause liver toxicity, which your doctor may monitor for using blood tests called liver function tests. Notify your healthcare provider if you notice yellowing of the skin or eyes, your urine appears dark or brown or pain in your abdomen, as these can be signs of liver toxicity.

This medication can also cause Hepatitis B reactivation in patients who have previously had hepatitis.  Be sure your healthcare provider is aware of previous Hepatitis B diagnosis and treatment. Your will also be tested for the Hepatitis B virus prior to beginning treatment with ofatumumab.

Tumor Lysis Syndrome

If your white blood cell (lymphocyte) count is very high prior to treatment, you are at risk for tumor lysis syndrome. This happens when the leukemia cells die too quickly and their waste overwhelms the body. You may be given a medication (allopurinol) and IV fluids to help prevent this. If you experience nausea, vomiting, diarrhea or become lethargic (drowsy, sluggish), notify your oncology team right away.

Reproductive Concerns

Exposure of an unborn child to this medication could cause birth defects, so you should not become pregnant or father a child while on this medication. Effective birth control is necessary during treatment. Even if your menstrual cycle stops or you believe you are not producing sperm, you could still be fertile and conceive.  You should consult with your healthcare team before breastfeeding while receiving this medication.


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