Ofatumumab belongs to the class of medications called selective immunomodulators. It is used to treat adults with relapsing remitting multiple sclerosis (RRMS) with active disease.

MS is a disease that affects the way the nerves in our body work. It is believed that MS is an autoimmune disease (a condition in which an individual's immune system starts reacting against their own tissues) and cannot be spread from person to person. In MS, for unknown reasons, the immune system sees the myelin sheath (a protective layer covering the nerves) as foreign and attacks it.

Ofatumumab is believed to affect the immune system by binding to a protein called CD20 on a certain type of white blood cells called B-cells. This helps to reduce the activity and number of the immune cells attacking the myelin sheath, slowing down damage to the nerves.

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.

The recommended starting dose of ofatumumab is 20 mg injected subcutaneously (under the skin) once weekly for 3 consecutive weeks (weeks 0, 1, and 2). Starting 2 weeks later (on week 4), the dose is reduced to 20 mg injected once per month.

Ofatumumab is administered by subcutaneous injection in the thigh or abdomen, or the upper outer arms, if someone else is giving you the injection. It is important to rotate the site of injection. Allow the medication to reach room temperature by removing it from the refrigerator for 15 to 30 minutes before injecting it. Do not heat the syringe or autoinjector to warm the medication. Do not shake this medication before using it. The solution for injection should be clear to slightly opalescent and colourless to slightly brownish-yellow. If it is cloudy or you can see lumps, flakes, or coloured particles in the solution, do not use it.

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.

It is important to take this medication exactly as prescribed by your doctor. If you miss a dose, take it as soon as possible. Take the next dose one month after that date, then continue with the monthly dosing schedule. Do not take a double dose to make up for a missed one. If you are not sure what to do after missing a dose, contact your doctor or pharmacist for advice.

Store this medication in the refrigerator in its original package, protect it from light, and do not freeze. Keep it out of the reach of children.

Each 0.4 mL of sterile solution for injection in the pre-filled Sensoready contains 20 mg of ofatumumab. Nonmedicinal ingredients: L-arginine, sodium acetate trihydrate, sodium chloride, polysorbate 80, disodium edetate dihydrate, hydrochloric acid, and water for injection.

Do not take this medication if you:

• are allergic to ofatumumab or any ingredients of the medication
• have active hepatitis B infection
• have any severe infection
• have or have had progressive multifocal leukoencephalopathy (PML)
• have a severely reduced immune system
• have active cancer

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.

• chills
• headache
• increased frequency of cold symptoms or sinus infections (e.g., sore throat, runny nose, nasal congestion or facial pain)
• muscle pain
• redness, pain, itching, or swelling at the injection site
• tiredness

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:

• fever
• signs of infection (symptoms may include fever or chills, severe diarrhea, shortness of breath, prolonged dizziness, headache, stiff neck, weight loss, or listlessness)

Stop taking the medication and seek immediate medical attention if any of the following occur:

• signs of a serious allergic reaction (e.g., abdominal cramps, difficulty breathing, nausea and vomiting, or swelling of the face and throat)

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.

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.

Hepatitis B reactivation: People who have hepatitis B infection that is dormant may experience the infection returning, causing further liver dysfunction or liver failure. 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 mediation, and whether any special monitoring is needed.

If you experience symptoms of worsening liver function, such as fatigue, feeling unwell, loss of appetite, nausea, yellowing of the skin or whites of the eyes, dark urine, pale stools, abdominal pain or swelling, and itchy skin, contact your doctor immediately.

Infections: Ofatumumab can affect the way your body's natural defenses work to fight infection. This makes the body more likely to develop infections due to bacteria, viruses, and fungi. This effect is increased if you are taking ofatumumab with other medications that reduce the body's ability to fight infection. If you have a history of chronic or frequent infections, 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.

Contact your doctor right away if you notice symptoms of a serious infection, such as fever, chills, headache, flu-like symptoms, feeling tired, cough, blood in the sputum, shortness of breath, night sweats, weight loss, nausea, vomiting, diarrhea, frequency or burning while passing urine, redness or swelling of skin or joints, cold sores, tooth pain, or new or worsening pain in any part of the body.

Progressive multifocal leukoencephalopathy (PML): There have been reports of PML after using ocrelizumab. PML is a rare disorder that causes nerve damage in the brain. If you experience memory loss, vision loss, trouble thinking, or difficulty walking, contact your doctor immediately.

Vaccinations: This medication may interfere with the effectiveness of certain vaccines. Before starting treatment with this medication, check with your doctor to ensure your immunizations are up to date. Any required vaccinations with live vaccines should be completed at least 4 weeks before starting and vaccinations with inactivated vaccines completed at least 2 weeks before starting treatment with ofatumumab.

Pregnancy: This medication should not be used during pregnancy unless the benefits outweigh the risks. If you become pregnant while taking this medication, contact your doctor immediately.

Women who may become pregnant should use effective birth control when receiving ofatumumab and for at least 6 months after treatment has ended.

Breast-feeding: It is not known if ofatumumab passes into breast milk. If you are breast-feeding 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.

Seniors: The safety and effectiveness of using this medication have not been established for adults older than 55 years of age.

There may be an interaction between ofatumumab and any of the following:

• BCG
• baricitinib
• denosumab
• dimethyl fumarate
• echinacea
• fingolimod
• leflunomide
• mitoxantrone
• natalizumab
• ocrelizumab
• ozanimod
• pimecrolimus
• roflumilast
• siponimod
• tacrolimus
• teriflunomide
• tofacitinib
• upadacitinib
• vaccines

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.