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Ofatumumab (Arzerra™)

Last Modified: January 14, 2012

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

About Ofatumumab

Ofatumumab is a type of monoclonal antibody, which is a group of medications that are designed to target a specific protein on the cell (in this case, CD20 on the B-cell lymphocyte). Antibodies, which are normally found in the body, are developed by the immune system to destroy foreign things (such as germs from bacteria or viruses). Ofatumumab is an antibody that is made in a laboratory, with the goal of stimulating the patient’s immune system to attack the cancer cells.

How to Take Ofatumumab

Ofatumumab is given by intravenous (into a vein) infusion in your oncologist’s office. Patients receive 12 doses over 7 months (8 weekly doses, followed by 4 weeks off therapy, followed by 4 monthly doses). Prior to each dose, the patient will receive premedications, including acetaminophen, an antihistamine and an IV corticosteroid (such as prednisolone), to prevent an infusion reaction.

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.

For more suggestions, read the Neutropenia Tip Sheet.

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. Read the anemia tip sheet for more information.

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.

Read the thrombocytopenia tip sheet for more information.

Nausea and/or Vomiting

Take anti-nausea medications as prescribed. If you continue to have nausea or vomiting, notify your doctor or nurse so they can help you manage this side effect. 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. Read the Nausea & Vomiting Tip Sheet for more suggestions.

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.


While on cancer treatment you may need to adjust your schedule to manage fatigue. Plan times to rest during the day and conserve energy for more important activities. Exercise can help combat fatigue; a simple daily walk with a friend can help. Talk to your healthcare team and see OncoLink’s section on fatigue for helpful tips on dealing with this side effect.


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 that absorbs fluid and can help relieve diarrhea. Foods high in soluble fiber include: applesauce, bananas (ripe), canned fruit, orange and grapefruit sections, boiled potatoes, white rice and 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. Read Low Fiber Diet for Diarrhea for more tips.

Decrease in Appetite

Visit OncoLink's section on Nutrition for tips on dealing with this side effect. Ask your nurse about nutritional counseling services.

  • Try to eat five or six small meals or snacks throughout the day, instead of 3 larger meals.
  • If you are not eating enough, nutritional supplements may help.
  • You may experience a metallic taste or dislike foods or beverages that you liked before receiving chemotherapy. These symptoms can last up to several months.
  • Avoid any food that you think smells or tastes bad. If red meat is a problem, eat chicken, turkey, eggs, dairy products and fish without a strong smell.
  • Flavor meat or fish by marinating it in sweet juices, sweet and sour sauce or dressings. Use seasonings like basil, oregano or rosemary. Bacon, ham and onion can also add flavor to vegetables.

Other Side Effects

In very rare cases, ofatumumab can cause a serious neurologic complication called progressive multifocal leukoencephalopathy (PML). Notify your oncology team immediately if you experience neurologic changes, such as confusion, dizziness, loss of balance, difficulty talking or walking or vision problems.

Ofatumumab can reactivate Hepatitis B, which can cause liver failure. You should notify your oncology team immediately if you notice worsening fatigue or yellow discoloration of the skin or eyes.

In clinical trials, some patients developed a bowel obstruction. Notify your oncology team if you develop abdominal pain, nausea or do not move your bowels for 3 days. Other side effects include rash and itching.


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