Abatacept belongs to a group of medications called selective co-stimulation modulators. It is used alone or with other medications to reduce signs and symptoms of rheumatoid arthritis and psoriatic arthritis.

Abatacept is used long-term to treat moderate-to-severe rheumatoid arthritis in adults that has not responded to treatment with one or more medications belonging to the class disease-modifying antirheumatic drugs (DMARDs) or the class tumour necrosis factor antagonists (TNF-a). When used long-term it may help to slow down the progression of joint damage and improve the function of the affected joints.

Abatacept is used to treat adults with active psoriatic arthritis that has had an inadequate response to other DMARDs.

It is also used to treat moderate-to-severe active juvenile idiopathic arthritis (JIA) or juvenile rheumatoid arthritis (JRA) in children age 6 years and older who have not responded to treatment with DMARDs.

People who have had a stem cell transplant may be given abatacept in addition to other medications to reduce the body's immune system to prevent graft-vs-host disease (GVHD).  

In people with rheumatoid arthritis and psoriatic arthritis, the immune system attacks normal tissues in the joints causing pain, inflammation, and damage. GVHD is a complication of a stem cell transplant, where the new immune cells attack the body.  Abatacept works by "turning down" parts of the body's immune system that are believed to be involved in these conditions and by keeping the immune system from attacking normal tissues.

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 being given this medication, speak to your doctor. Do not stop receiving this medication without consulting your doctor.

The recommended dose of abatacept varies according to body weight.

Abatacept can be given as an intravenous (into a vein) infusion or a subcutaneous (under the skin) injection.    For intravenous infusions, the dose is based on body weight. The appropriate dose is usually given once every 2 weeks for the first 3 doses, and once every 4 weeks after that. Intravenous infusions take approximately 30 minutes and are given by a health care professional, usually in a clinical setting such as a hospital clinic. When abatacept is used to prevent GVHD, 4 doses are given by intravenous infusion on specific days relative to the cell transplant date.

If you are using subcutaneous abatacept, the first dose is given by your health care provider. The usual dose is 125 mg injected once a week.

Subcutaneous abatacept is available as single-use prefilled syringes. It is used with the guidance and supervision of a doctor. Your doctor or nurse will assist you in the preparation and injection of your first dose (or first few doses). Do not attempt to inject this medication on your own until you completely understand how to inject a dose.

There are special directions enclosed in the package with the injection. Read these directions carefully before using the medication. Follow the instructions closely to avoid accidentally contaminating the medication or needle and giving yourself an infection, or from damaging the equipment or losing the medication.

Rotate the injection sites (arms, thighs, upper buttocks, or stomach) to minimize injection site skin irritation.

Many things can affect the dose and schedule of medication that a person needs, such as body weight, other medical conditions, and other medications. Your doctor may choose a schedule different from the one above.

It is important to receive this medication exactly as recommended by your doctor. If you miss an appointment to receive abatacept, contact your doctor as soon as possible to reschedule your appointment.

This medication is stored in the refrigerator at 2°C to 8°C, protected from light, and kept from freezing.

125 mg/mL prefilled syringes
Each 1 mL of sterile, clear, colourless-to-pale-yellow, preservative-free, ready-to-use solution for subcutaneous injection in a single-use prefilled syringe contains 125 mg of abatacept. Nonmedicinal ingredients: sucrose, poloxamer 188, monobasic sodium phosphate monohydrate, dibasic sodium phosphate anhydrous, and water for injection.

250 mg/vial
Each vial of sterile powder contains 250 mg of abatacept. Nonmedicinal ingredients: maltose, sodium chloride, and sodium phosphate monobasic.

Do not use abatacept if you:

• are allergic to abatacept or any ingredients of the medication
• have or are at risk of sepsis syndrome (an infection that spreads through your body), such as people with weakened immune systems and people with HIV

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.

• diarrhea
• fatigue
• headache
• nausea
• sore throat

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 or chills
• signs of a skin infection (e.g., redness, inflammation, swelling, warmth)
• signs of a urinary tract or kidney infection (e.g., pain or burning sensation when urinating, frequent urination, blood in the urine, back pain)
• signs of an intestinal infection (e.g., abdominal pain, change in bowel habits, fever, nausea)
• signs of pneumonia or bronchitis (e.g., cough, fever, shortness of breath, chest pains)
• upper respiratory infections (e.g., colds, sore throats, or sinus infections) – especially if symptoms won't go away or keep coming back

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

• signs of an allergic reaction (e.g., difficulty breathing, hives, swelling of the face or throat, chest pain)

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.

Allergic reactions: In rare cases, some people may develop an allergic reaction to this medication. Signs of an allergic reaction include a severe rash, swollen face, chest pain, or difficulty breathing. If these occur, contact your doctor immediately.

Blood glucose: The intravenous form of this medication may affect blood glucose testing by giving falsely high blood glucose readings with certain types of blood glucose monitors. If you require blood glucose monitoring, talk to your doctor or pharmacist about using a blood glucose monitor that will not be affected by this medication. The subcutaneous form of this medication does not have the same effect.

Cancer: In clinical trials, people using abatacept reported developing lung cancer or a cancer of the immune system (known as lymphoma) more often than people who were given an inert treatment. Other types of cancer have also been reported. The number of reported cancer cases in people taking abatacept appears to be consistent with the expected number of cancer cases reported in people with rheumatoid arthritis. In general, people with severe rheumatoid arthritis who have had the condition for a long time may also have a higher risk of developing lymphoma. If you take abatacept or another rheumatoid arthritis biologic medication, your risk may increase. The role of abatacept in the development of cancer is not known.

Chronic obstructive pulmonary disease (COPD): People with COPD have a higher risk of experiencing side effects when they are using abatacept. If you have COPD, your doctor will monitor you for signs of worsening disease.

Infections: This medication can increase the risk of developing an infection. If you notice signs of an infection, such as fever, chills, pain, swelling, or pus, contact your doctor as soon as possible. Also, this medication should not be started while you have an active or chronic infection. This medication is not recommended for use by people who have active tuberculosis or if you come in contact with someone who has tuberculosis. Your doctor may examine you for tuberculosis and give you a skin test before you start abatacept.

People infected with hepatitis B virus (an infection that can damage the liver) have had a relapse of their condition while taking abatacept. To determine if you are at risk for any infections becoming reactivated, your doctor may test you for these infections before starting treatment with abatacept and will follow your condition closely while you are taking the medication. If you notice symptoms of liver problems, such as abdominal pain, yellow eyes or skin, loss of appetite, fatigue, or dark urine, contact your doctor immediately.

Use with other biologics: This medication should not be used at the same time with a class of medications called biologic response modifiers ("biologics") and other such medications (e.g., anakinra, etanercept, infliximab, adalimumab, rituximab). Doing so could increase the risk of infections.

Vaccines: Live vaccines should not be given during treatment with abatacept or within 3 months of stopping abatacept. Children who have JIA or JRA should complete the recommended vaccination schedule before starting treatment with abatacept.

Pregnancy: There have been no studies on the use of abatacept by pregnant women. 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.

Breast-feeding: It is not known if abatacept 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 the intravenous form of abatacept have not been established for children less than 6 years of age. The subcutaneous form of this medication has not been studied for use by children and adolescents. It is not recommended for this age group.

Seniors: Seniors may be more likely to experience serious infections and cancer with abatacept. Talk to your doctor about the risks and benefits of using this medication.

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

• adalimumab
• anakinra
• baricitinib
• BCG
• belimumab
• certolizumab
• cladribine
• denosumab
• etanercept
• golimumab
• infliximab
• leflunomide
• lenalidomide
• natalizumab
• nivolumab
• ocrelizumab
• pimecrolimus
• pomalidomide
• rituximab
• sarilumab
• sphingosine 1-phosphate receptor (S1P) receptor inhibitors (e.g., fingolimod, ponesimod, siponimod)
• tacrolimus
• thalidomide
• tocilizumab
• tofacitinib
• upadacitinib
• vaccines (e.g., measles, mumps, and rubella [MMR], tuberculosis [BCG], yellow fever)

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.