Ofatumumab is used to treat a certain type of leukemia (CLL - chronic lymphocytic leukemia) in patients who have not responded to other cancer chemotherapy drugs (such as fludarabine, alemtuzumab). Ofatumumab belongs to a class of drugs known as monoclonal antibodies. This medication works by stopping the growth of cancer cells.

This medication is given by injection into a vein by a health care professional. It is usually given once a week for the first 8 doses, then once every 4 weeks for the last 4 doses or as directed by your doctor.

The dosage is based on your medical condition and response to treatment. To prevent side effects, your doctor may prescribe other medications before each treatment, including acetaminophen, an antihistamine (such as diphenhydramine), and a corticosteroid (such as methylprednisolone).

This medication may cause very serious (rarely fatal) infusion-related reactions during or up to 24 hours after treatment. These reactions occur more often during the first and second treatments. Your doctor will monitor you closely and increase your dose slowly to reduce the chances of these serious side effects. If you have a reaction, your treatment will be temporarily stopped. Tell your doctor or nurse immediately if any of these effects occur: chest pain, flushing, wheezing, trouble breathing, dizziness, fainting, pounding/irregular heartbeat, fever, chills, back/stomach pain, or rash/itching.

See also How to Use section.

Nausea, vomiting, diarrhea, tiredness, swelling of hands/ankles/feet, or trouble sleeping may occur. If any of these effects persist or worsen, tell your doctor or pharmacist promptly.

Many people using this medication have serious side effects. However, your doctor has prescribed this drug because he or she has judged that the benefit to you is greater than the risk of side effects. Careful monitoring by your doctor may decrease your risk.

This medication decreases bone marrow function, an effect that may lead to a low number of blood cells such as red cells, white cells, and platelets. This effect can cause anemia, decrease your body's ability to fight an infection, or cause easy bruising/bleeding. Your doctor will order blood tests to check for this side effect. It is important to keep all medical/lab test appointments. Tell your doctor immediately if you develop any of the following symptoms: easy bruising/bleeding, pale skin, unusual tiredness, signs of infection (such as fever, chills, cough, persistent sore throat).

Ofatumumab may rarely cause serious (possibly fatal) liver disease in people exposed to hepatitis B virus. Your doctor may order blood tests and watch for symptoms during treatment and for 6 to 12 months after your last treatment. Seek immediate medical attention if you have any symptoms of liver damage, including: persistent nausea/vomiting, stomach/abdominal pain, dark urine, yellowing eyes/skin.

Ofatumumab increases your risk of getting a rare but very serious (sometimes fatal) brain infection (progressive multifocal leukoencephalopathy-PML). Tell your doctor immediately if any of these rare but very serious side effects occur: loss of balance/dizziness, confusion, difficulty walking or talking, seizure, vision changes.

A very serious allergic reaction to this drug is rare. However, seek immediate medical attention if you notice any symptoms of a serious allergic reaction, including: rash, itching/swelling (especially of the face/tongue/throat), severe dizziness, trouble breathing.

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US -

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before receiving this medication, tell your doctor or pharmacist if you are allergic to it; or if you have ever had a severe reaction to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of: breathing problems (such as chronic obstructive pulmonary disease - COPD, asthma), liver disease (such as hepatitis B), heart disease (such as chest pain, heart attack), immune system problems (such as HIV).

This drug may make you dizzy. Do not drive, use machinery, or do any activity that requires alertness until you are sure you can perform such activities safely. Limit alcoholic beverages.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Ofatumumab can make you more likely to get infections or may worsen any current infections. Therefore, wash your hands well to prevent the spread of infection. Avoid contact with people who have infections that may spread to others (such as chickenpox, measles, flu). Consult your doctor if you have been exposed to an infection or for more details.

Do not have immunizations/vaccinations without the consent of your doctor. Avoid contact with people who have recently received live vaccines (such as flu vaccine inhaled through the nose).

To lower the chance of getting cut, bruised, or injured, use caution with sharp objects like razors and nail cutters, and avoid activities such as contact sports.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

It is unknown whether this drug passes into breast milk and may have undesirable effects on a nursing infant. Consult your doctor before breast-feeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug include: other drugs that weaken the immune system/increase the risk of infection (such as natalizumab, rituximab).

If overdose is suspected, contact a poison control center or emergency room immediately. US residents can call their local poison control center at 1-800-222-1222. Canada residents can call a provincial poison control center.

Laboratory and/or medical tests (such as complete blood count, platelets, liver function tests) should be performed periodically to monitor your progress or check for side effects. Consult your doctor for more details.

Keep all regular medical and laboratory appointments.

For the best possible benefit, it is important to receive each scheduled dose of this medication as directed. If you miss a dose, contact your doctor or pharmacist immediately to establish a new dosing schedule.

Not applicable. This medication is given in a hospital or clinic and will not be stored at home.

MEDICAL ALERT: Your condition can cause complications in a medical emergency. For information about enrolling in MedicAlert, call 1-888-633-4298 (US) or 1-800-668-1507 (Canada).

Information last revised March 2013. Copyright(c) 2013 First Databank, Inc.