How does this medication work? What will it do for me?
Ofatumumab belongs to the class of medications called monoclonal antibodies. It is used to treat chronic lymphocytic leukemia (CLL), which is a cancer of the blood that affects white blood cells. In CLL, white blood cells are made too quickly and live too long. Too many white blood cells cause problems in the body. Ofatumumab works by attaching to the tumour cells and stimulating the body's defenses, resulting in the death of tumour cells.
Ofatumumab is used in combination with a medication called chlorambucil to treat CLL in people who have not been previously treated. Ofatumumab may also be used by people with CLL that has not responded to other treatments.
This medication may be available under multiple brand names and/or in several different forms. Any specific brand name of this medication may not be available in all of the forms or approved for all of the conditions discussed here. As well, some forms of this medication may not be used for all of the conditions discussed here.
Your doctor may have suggested this medication for conditions other than those listed in these drug information articles. If you have not discussed this with your doctor or are not sure why you are taking this medication, speak to your doctor. Do not stop taking this medication without consulting your doctor.
Do not give this medication to anyone else, even if they have the same symptoms as you do. It can be harmful for people to take this medication if their doctor has not prescribed it.
What form(s) does this medication come in?
Each 1 mL of sterile, clear to opalescent, colourless, preservative free liquid concentrate contains 20 mg ofatumumab. Nonmedicinal ingredients: arginine, sodium acetate, sodium chloride, polysorbate 80, edetate disodium, hydrochloric acid, and water for injection.
How should I use this medication?The recommended dose of ofatumumab for people who have not yet received any treatment is 300 mg given by intravenous (into a vein) infusion on day 1, followed by 1000 mg on day 8 of a 28-day cycle. After these 2 doses, 1000 mg is given once every 4 weeks.
The recommended first dose of ofatumumab for people who have received other treatments is 300 mg given by intravenous (into a vein) infusion. After this first dose, 2000 mg is given once a week for 8 weeks, then once every 4 weeks for 4 months.
You may be given medications before each infusion of ofatumumab to help decrease reactions to the infusion. These medications include anithistamines, steroids, and pain relievers.
Many things can affect the dose of medication that a person needs, such as body weight, other medical conditions, and other medications. If your doctor has recommended a dose different from the ones listed here, do not change the way that you are taking the medication without consulting your doctor.
Ofatumumab is usually injected into a vein through a site on your skin that has been specially prepared for this purpose. Very careful handling of this medication is required. Ofatumumab is always given under the direct supervision of a doctor in a hospital or similar setting with access to sterile equipment for preparation.
It is important this medication be given exactly as recommended by your doctor. If you miss an appointment to receive a dose of ofatumumab contact your doctor as soon as possible to reschedule your appointment.
Do not dispose of medications in wastewater (e.g. down the sink or in the toilet) or in household garbage. Ask your pharmacist how to dispose of medications that are no longer needed or have expired.
Who should NOT take this medication?
Do not take ofatumumab if you:
- are allergic to ofatumumab or any ingredients of the medication
- have or have had progressive multifocal leukoencephalopathy (PML)
What side effects are possible with this medication?
Many medications can cause side effects. A side effect is an unwanted response to a medication when it is taken in normal doses. Side effects can be mild or severe, temporary or permanent.
The side effects listed below are not experienced by everyone who takes this medication. If you are concerned about side effects, discuss the risks and benefits of this medication with your doctor.
The following side effects have been reported by at least 1% of people taking this medication. Many of these side effects can be managed, and some may go away on their own over time.
Contact your doctor if you experience these side effects and they are severe or bothersome. Your pharmacist may be able to advise you on managing side effects.
- back pain
- swelling of the hands, feet and ankles
Although most of the side effects listed below don't happen very often, they could lead to serious problems if you do not seek medical attention.
Check with your doctor as soon as possible if any of the following side effects occur:
- signs of anemia (low red blood cells; e.g., dizziness, pale skin, unusual tiredness or weakness, shortness of breath)
- signs of bleeding (e.g., bloody nose, blood in urine, coughing blood, bleeding gums, cuts that don't stop bleeding)
- signs of infection (symptoms may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)
- signs of an infusion reaction (e.g., nausea, high temperature, rash)
- signs of pneumonia (e.g., cough, fever, difficulty breathing)
Stop taking the medication and seek immediate medical attention if any of the following occur:
- severe infusion reactions (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat, flushing, high blood pressure, shortness of breath, chills/rigors, fever, diarrhea)
- signs of bowel obstruction (persistent abdominal pain, constipation, diarrhea, bloating)
- signs of a heart attack (e.g., chest pain or pressure, pain extending through shoulder and arm, nausea and vomiting, sweating)
- signs of tumour lysis syndrome (e.g., muscle spasms, producing less urine than usual, nausea, cloudy urine, shortness of breath)
Some people may experience side effects other than those listed. Check with your doctor if you notice any symptom that worries you while you are taking this medication.
Are there any other precautions or warnings for this medication?
Before you begin using a medication, be sure to inform your doctor of any medical conditions or allergies you may have, any medications you are taking, whether you are pregnant or breast-feeding, and any other significant facts about your health. These factors may affect how you should use this medication.
Anemia: Ofatumumab may cause low levels of red blood cells. If you experience symptoms of reduced red blood cell count (anemia) such as shortness of breath, feeling unusually tired, or pale skin, contact your doctor as soon as possible.
Your doctor will do blood tests regularly to monitor the number of specific types of blood cells, including red blood cells, in your blood.
Blood clotting: This medication can reduce the number of platelet cells in the blood. Platelets help the blood to clot, and a shortage could make you bleed more easily. Tell your doctor of any signs that your blood is not clotting as quickly as usual. Such symptoms may include black and tarry stools, blood in the urine, easy bruising, or cuts that won't stop bleeding.
Your doctor will do blood tests regularly to monitor the number of specific types of blood cells, including platelets, in your blood.
Bowel obstruction: A blockage in the digestive tract has been reported by people taking ofatumumab and other similar medications. If you experience persistent abdominal pain, constipation, diarrhea, or bloating while you are using this medication, contact your doctor as soon as possible.
Heart disease: Serious blood pressure changes, fluid build-up around the lungs, and heart attack may occur with the use of this medication. If you have a history of heart problems, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Hepatitis B infection: As it kills cancer cells, ofatumumab also damages the cells that are responsible for protecting the body from infection. If you have hepatitis B infection or are a carrier of the hepatitis B virus, this may allow the hepatitis B infection to flare up, possibly causing fatal liver damage. If you have a history of hepatitis B infection, discuss with your doctor how this medication may affect your medical condition, how your medical condition may affect the dosing and effectiveness of this medication, and whether any special monitoring is needed.
Infection: As well as killing cancer cells, ofatumumab can reduce the number of cells that fight infection in the body (white blood cells). If possible, avoid contact with people with contagious infections.
Tell your doctor immediately if you notice signs of an infection, such as fever or chills, severe diarrhea, cough, shortness of breath, prolonged dizziness, headache, stiff neck, or listlessness. Your doctor will do blood tests regularly to monitor the number of specific types of blood cells in your blood.
Infusion Reactions: This medication can cause a hypersensitivity or infusion reaction. Symptoms of this type of reaction generally appear during the infusion of the medication and may include flushing, chest pain, shortness of breath and a dramatic drop in blood pressure. These reactions can be fatal if a health care provider is not informed immediately.
Progressive multifocal leukoencephalopathy (PML): This is a rare disease of the brain that is caused by viruses attacking the nerve cells in the brain. Rarely, it may occur when using medications like ofatumumab. If you have had a previous episode of PML, ofatumumab is not an appropriate medication for you. Contact your doctor immediately if you experience signs and symptoms of PML, such as unusual clumsiness, memory loss, gradually worsening weakness, and possible visual, speech or personality changes.
Tumour lysis syndrome: Ofatumumab, like many other cancer medications, causes many cancer cells to be suddenly killed when treatment is first started. This can overwhelm the body with waste products from the cells. As a result, the body may not be able to keep up with getting rid of all the waste. When this happens, you may experience nausea, shortness of breath, cloudy urine, or joint pain. This is called tumour lysis syndrome. Your doctor may prescribe some medications to help your body get rid of the waste products. Make sure you understand how to use these medications and report any of these signs or symptoms to your doctor immediately.
Pregnancy: There is no information about the effect of ofatumumab on an unborn baby if this medication is used during pregnancy. Effective birth control should be practiced while using this medication and for 6 months after your last treatment. If you become pregnant while taking this medication, contact your doctor immediately.
Breast-feeding: It is not known if ofatumumab passes into breast milk. If you are a breast-feeding mother and are taking this medication, it may affect your baby. Talk to your doctor about whether you should continue breast-feeding.
Children: The safety and effectiveness of using this medication have not been established for children.
What other drugs could interact with this medication?
There may be an interaction between ofatumumab and any of the following:
- BCG vaccine
- tacrolimus (topical)
If you are taking any of these medications, speak with your doctor or pharmacist. Depending on your specific circumstances, your doctor may want you to:
- stop taking one of the medications,
- change one of the medications to another,
- change how you are taking one or both of the medications, or
- leave everything as is.
An interaction between two medications does not always mean that you must stop taking one of them. Speak to your doctor about how any drug interactions are being managed or should be managed.
Medications other than those listed above may interact with this medication. Tell your doctor or prescriber about all prescription, over-the-counter (non-prescription), and herbal medications you are taking. Also tell them about any supplements you take. Since caffeine, alcohol, the nicotine from cigarettes, or street drugs can affect the action of many medications, you should let your prescriber know if you use them.
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