Drug Formulary information is intended for use by healthcare professionals. It is not intended to be medical advice. Some of the information, including information about funding for cancer drugs, does not apply to all patients. Cancer treatment plans are unique to each patient. If you are a patient, please speak with your healthcare team to understand how this information applies to you.

drug-infosheet

oFAtumumab

Other Names
Arzerra®
Appearance
Clear, colourless solution
Medication Information Sheet
oFAtumumab (OH-fa-TUE-mue-mab)
This document provides general information about your medication. It does not replace the advice of your health care professional. Always discuss your therapy with your health care professional and refer to the package insert for more details.

Other Name: Arzerra®

Appearance:
Clear, colourless solution

What is this medication for?
  • For treating patients with chronic lymphocytic leukemia (CLL) given alone, or in combination with another medication.

What should I do before I have this medication?
  • Tell your doctor if you have/had significant medical condition(s), especially if you have / had heart or lung problems, hepatitis or liver disease, active infections or history of infections, or if you have any allergies.
  • Your doctor will test your blood for exposure to hepatitis B virus before starting treatment
  • People who have cancer or leukemia are at a higher risk of developing other cancers/leukemias (usually some years later) or blood clots. Some cancer medications may increase these risks, especially if used for a prolonged period of time. You should discuss any concerns with your doctor.
How will this medication affect sex, pregnancy and breastfeeding?
  • oFAtumumab can harm the unborn baby and should not be used by pregnant women.
  • If there is ANY chance that you or your partner may become pregnant, you and your partner together must: ► Use 2 effective forms of birth control at the same time while receiving this drug: Keep using birth control until at least 6 months after the last dose (general recommendation). Discuss with your healthcare team.
  • Tell your doctor right away if you or your partner becomes pregnant.
  • Do not breastfeed while using this drug
  • Effects on Fertility: Unlikely
  • Effects on Fertility: Unlikely
How is this medication given?
  • This drug is given by injection into a vein.

  • This drug will be given over a longer period of time for the first cycle. If you have no problems with this infusion, it will be given over a shorter time for the following cycles.

  • You will be given drug(s) before ofatumumab to prevent a reaction.

What else do I need to know while on this medication?
  • Although it is unlikely that other medications can affect your treatment, make sure your health care team knows about all of your medicines (prescription or over-the-counter medications, herbals and supplements). Check with your health care team before starting or stopping any of them.

  • For mild aches and pain:

    • You may take acetaminophen (Tylenol®) tablets. Ask your health care team about the right dose for you. 
    • Ibuprofen (Advil®, Motrin®), naproxen (Aleve®) or aspirin (acetylsalicylic acid, ASA), including low dose aspirin for heart conditions, may increase your chance of bleeding.
    • Talk to your health care team before you start or stop these medications.
    • If you feel unwell, take your temperature before taking any of these medications. They may hide a fever. 
    • Talk to your health care team or go to the closest emergency room right away if you have a fever.  See the Fever pamphlet for more information.
What are the side effects of this medication?

Common side effects usually occur in more than 1 out of every 10 patients. Other side effects are less common, but may be severe. You may not have all of the side effects below. You may have side effects that are not listed.

Side effects and what to do When to contact doctor?
More Common Side Effects

Cough; Feeling short of breath

 

 

 

Contact your health care team if no improvement or if severe

Unusual bleeding or bruising

You may have black stools, cough up blood, blood in your urine, purple or red dots on your skin or bleeding that will not stop. 

Fever, chills, infection

You have a fever if your temperature taken in your mouth (oral temperature) is:

  • 38.3°C (100.9°F) or higher at any time OR
  • 38.0°C (100.4°F) or higher for at least one hour.

While you are getting chemotherapy treatments:

  • Keep a digital thermometer at home and take your temperature if you feel hot or unwell (for example, chills).
  • Avoid taking medications that treat a fever before you take your temperature (for example, Tylenol®, acetaminophen, Advil® or ibuprofen) as they may hide a fever.
  • Do not eat or drink anything hot or cold right before taking your temperature.
  • Wash your hands often.
  • Check with your doctor before getting any vaccines, surgeries or visiting your dentist.

If you have a fever, talk to your health care team or go to the closest emergency room. 
See our Neutropenia (Low white blood cell count) pamphlet for more information.

Get emergency medical help right away

Diarrhea

  • May occur days to weeks after the drug is given / after treatment starts.
  • Drink plenty of clear fluids. Limit hot, spicy, fried foods, foods/drinks with caffeine (coffee, tea or cola), orange or prune juice. Try a low-fiber BRAT diet (Bananas, white Rice, Apple sauce, Toast made with white bread).
  • Take anti-diarrhea drug(s) if given to you by your doctor.
  • Also see Diarrhea pamphlet.*
Contact your health care team if no improvement or if severe

Tiredness

  • Rest often; take naps if needed. Move slowly when getting up.
  • Eat well-balanced meals and drink plenty of fluids. Light exercise may help.
  • If you are feeling tired, avoid driving or operating machinery
Contact your health care team if no improvement or if severe

Infections that happen when the immune system is impaired (usually by viruses, bacteria or fungi that would not normally result in infections in patients with normal immunity)

Get emergency medical help right away

Nausea and vomiting (generally mild)

  • May occur in hours to days after the dose is given/ after treatment starts.
  • Drink clear fluids and avoid large meals. Get fresh air and rest.
  • Limit spicy, fried foods or foods with a strong smell.
  • Take anti-nausea drug(s) exactly as directed by your doctor. It is easier to prevent nausea than to treat it.
  • Contact your doctor if nausea lasts more than 48 hours or vomiting for more than 24 hours.
  • Also see Nausea & Vomiting pamphlet.*
Contact your health care team if no improvement or if severe

Rash; dry, itchy skin (may be severe)

  • Stay out of the sun; wear sunblock, a hat and cover exposed skin.
  • Use daily moisturizer.
  • Severe rash may occur on the body/limbs with blistering or peeling of skin:  Get emergency medical help right away if this occurs.
Contact your health care team if no improvement or if severe

Mild swelling in arms and legs; puffiness

  • Keep your feet up when sitting. Eat a low-salt diet.
  • Avoid tight fitting clothing.
Contact your health care team if no improvement or if severe

Headache; mild joint, muscle pain or cramps 

  • Take painkiller(s) as directed, if given to you by your doctor.
  • Otherwise, take acetaminophen (Tylenol®) tablets as needed for mild aches and pains. Ask your doctor or pharmacist about the right dose for you.
  • Rest often, but may try light exercise.
Contact your health care team if no improvement or if severe

Side effects and what to do When to contact doctor?
Less Common Side Effects, but may be Severe

Heart problems
(irregular heartbeat, chest pain, fainting, swelling in legs/ankles/belly, shortness of breath)

 

 

Get emergency medical help right away

Drug reaction (fever, severe rash, itchiness, flushing, dizziness, shortness of breath, chest or throat tightness)

  • You may be given medicines to prevent or treat this reaction
  • May occur during or shortly after the drug is given.
Get emergency medical help right away

Blood clot (limb pain or swelling, hardened vein in limb), may occur in lungs (sudden start of coughing, breathing problems, chest pain, coughing blood)

Blockage of an artery (blood vessel) in your heart, brain, chest, belly, or limbs; this may result in stroke (sudden loss of vision, speech, or the use of your limb(s)) or heart attack (chest pain, shortness of breath), or pain in chest, belly or limb

Get emergency medical help right away

Blocked intestines
(severe belly pain, bloating, severe constipation)

Get emergency medical help right away

Effects on the brain (confusion, difficulty with thinking, speaking, movement or balance, blurred and/or loss of vision, weakness on one side of the body)

Get emergency medical help right away

Rapid killing of cancer cells when you start treatment may lead to build up of cell waste products

  • If mild, this may cause gout, with joint pains, but if severe, may cause fevers, kidney failure, confusion and be life-threatening.
  • You MUST take the preventive medicines given by your doctor AND
  • Drink plenty of fluids (6-8 glasses per day) and void (urinate) frequently.
Get emergency medical help right away

For more links on how to manage your symptoms go to https://www.cancercareontario.ca/en/symptom-management.

The information set out in the medication information sheets, regimen information sheets, and symptom management information (for patients) contained in the Drug Formulary (the "Formulary") is intended to be used by health professionals and patients for informational purposes only. The information is not intended to cover all possible uses, directions, precautions, drug interactions or side effects of a certain drug, nor should it be used to indicate that use of a particular drug is safe, appropriate or effective for a given condition.

A patient should always consult a healthcare provider if he/she has any questions regarding the information set out in the Formulary. The information in the Formulary is not intended to act as or replace medical advice and should not be relied upon in any such regard. All uses of the Formulary are subject to clinical judgment and actual prescribing patterns may not follow the information provided in the Formulary.

Last Updated: July 27, 2026