Belimumab

Pronunciation: be-lim-ue-mab
Generic name: belimumab
Brand name: Benlysta
Dosage form: single-dose vial for intravenous infusion (120 mg/vial, 400 mg/vial), prefilled syringe for subcutaneous use (200 mg/mL), prefilled autoinjector for subcutaneous use (200 mg/mL)
Drug class: Selective immunosuppressants

Medically reviewed by Carmen Pope, BPharm. Last updated on Jun 30, 2025.

What is belimumab?

Belimumab is used to treat active systemic lupus erythematosus (SLE) or active lupus nephritis in adults and children 5 years of age and older. The brand name is Benlysta. It is given by subcutaneous injection or intravenous infusion every 1 to 2 weeks, depending on the age of the patient.

Belimumab works by targeting and blocking a protein called B-lymphocyte stimulator (BLyS) that helps B cells survive and produce antibodies. In lupus, B cells are overactive and produce harmful autoantibodies that attack healthy tissue. By blocking BLyS, belimumab reduces the survival of B cells, decreases the production of autoantibodies, and helps control the overactive immune response. This improves symptoms such as fatigue, and reduces flares associated with SLE and lupus nephritis. 

Belimumab gained FDA approval on March 9, 2011, under the brand name Benlysta, made by GlaxoSmithKline LLC. There is no generic or biosimilar.

FDA approvals and uses

Belimumab is used to treat adults and children aged 5 years and older with:

• active systemic lupus erythematosus (SLE) when used with standard therapy
• active lupus nephritis when used with standard therapy.

Belimumab should not be used in patients with severe active central nervous system lupus, as its effectiveness has not been evaluated.

The autoinjector can be used for subcutaneous administration in adults and children aged 5 and older, weighing at least 15 kg. The prefilled syringe has not been studied in children less than 18 years of age.

Side effects

The most common side effects of belimumab are:

• nausea
• diarrhea
• fever
• sore throat, runny or stuffy nose (nasopharyngitis)
• persistent cough (bronchitis)
• bronchitis
• pain, itching, redness, or swelling where an injection was given under the skin
• pain in your arms or legs
• headache (migraine)
• depression
• sleep problems (insomnia).

Serious side effects and warnings

Belimumab may cause the following serious side effects:

• Infections. Infections could be serious, leading to hospitalization or death. Tell your healthcare provider right away if you have any of the following symptoms of an infection:
  • fever
  • urinating often
  • chills
  • coughing up mucus
  • pain or burning with urination
  • warm, red, or painful skin or sores on your body.
• Allergic (hypersensitivity) reactions. Serious allergic reactions can happen on the day of, or in the days after, receiving belimumab and may cause death. Your healthcare provider will watch you closely while you are receiving belimumab, given intravenously and after your infusion for signs of a reaction. Allergic reactions can sometimes be delayed. Tell your healthcare provider right away if you have any of the following symptoms of an allergic reaction following use of belimumab:
  • itching
  • low blood pressure
  • swelling of the face, lips, mouth, tongue, or throat
  • dizziness or fainting
  • headache
  • trouble breathing
  • nausea
  • anxiousness
  • skin rash.
• Mental health problems and suicide. Symptoms of mental health problems can occur. Tell your healthcare provider right away if you have any of the following symptoms:
  • thoughts of suicide or dying
  • new or worse depression
  • attempt to commit suicide
  • acting on dangerous impulses
  • trouble sleeping (insomnia)
  • unusual changes in your behavior or mood
  • new or worse anxiety
  • thoughts of hurting yourself or others.
• Progressive multifocal leukoencephalopathy (PML). PML is a serious and life-threatening brain infection. Your chance of getting PML may be higher if you are treated with medicines that weaken your immune system, including belimumab. PML can result in death or severe disability. If you notice any new or worsening medical problems such as those below, tell your healthcare provider right away:
  • memory loss
  • trouble thinking
  • dizziness or loss of balance
  • difficulty talking or walking
  • loss of vision.
• Cancer. Belimumab may reduce the activity of your immune system. Medicines that affect the immune system may increase your risk of certain cancers.

Live vaccines should not be given concurrently with this medicine.

This is not a complete list of side effects, and others may occur. Call your doctor for medical advice about side effects. You may report side effects to the FDA at 1-800-FDA-1088.

Related/similar drugs

Before receiving

Do not receive a belimumab injection or infusion if you are allergic to the active ingredient belimumab, Benlysta, or any of the inactive ingredients in the injection or infusion.

Before receiving, tell your healthcare provider about all your medical conditions, including if you:

• think you have an infection or have infections that keep coming back. You should not receive belimumab if you have an infection unless your healthcare provider tells you to
• have or have had mental health problems, such as depression or thoughts of suicide
• have recently received a vaccination, or if you think you may need a vaccination. If you are receiving Belimumab, you should not receive live vaccines, such as measles, mumps, or varicella
• are allergic to other medicines
• are receiving certain medicines, such as cyclophosphamide or other monoclonal antibodies
• have or have had cancer
• are pregnant or plan to become pregnant
• are breastfeeding or plan to breastfeed.

This medicine may increase your risk of certain cancers by changing the way your immune system works. Ask your doctor about your risk.

Some people have thoughts about suicide while using belimumab. Your doctor will need to check your progress at regular visits. Your family or other caregivers should also be alert to changes in your mood or symptoms.

Pregnancy

It is not known if belimumab injection or infusion will harm your unborn baby or affect its immune system. You should talk to your healthcare provider about whether to prevent pregnancy while on belimumab. If you choose to prevent pregnancy, you should use an effective method of birth control while receiving belimumab and for at least 4 months after the final dose.

Tell your healthcare provider right away if you become pregnant during your treatment with belimumab or if you think you may be pregnant. If you become pregnant while receiving belimumab, talk to your healthcare provider about enrolling in the Benlysta Pregnancy Registry. You can enroll in this registry by calling 1-877-311-8972 or going to MotherToBaby to enroll. The purpose of this registry is to collect information about you and your baby's health.

Breastfeeding

It may not be safe to breastfeed while using belimumab. Ask your doctor about any risks.

How is belimumab administered?

Belimumab may be administered into a vein by a healthcare provider (this is called an IV infusion) or given under the skin (this is called subcutaneously), either by self-administration or by a healthcare provider.

Intravenous administration

You will be given your belimumab infusion by a healthcare provider through a needle placed in a vein (IV infusion).

• It takes about 1 hour to give you the full dose of belimumab, but you may need premedications beforehand or stay for a short time after to monitor for any infusion-related reactions.
• Belimumab infusion is usually administered every 2 to 4 weeks, depending on the age of the person being treated.
• Your healthcare provider may give you medicines before you receive belimumab to help reduce your chance of having a reaction.
• A healthcare provider will watch you closely while you are receiving belimumab and after your infusion for signs of a reaction.

Subcutaneous administration

Belimumab for subcutaneous injection can be self-administered or given by a caregiver.

• It is usually given 1 time a week or 1 time every 2 weeks, depending on the age of the patient.
• It can be injected under the skin (subcutaneously) of your stomach (abdomen) or thigh.
• Read the Instructions for Use that comes with Belimumab Package Insert for instructions about the right way to give your injections at home.

Belimumab injection for SC use may be prescribed as a single-dose autoinjector or as a single-dose prefilled syringe.

• The autoinjector can be used for subcutaneous administration in adults and children aged 5 and older, weighing at least 15 kg.
• The prefilled syringe has not been studied in children less than 18 years of age.

Dosing information

The dose of belimumab depends on the age of the patient and administration (IV or SC).

Intravenous Dose of Belimumab for SLE or Lupus Nephritis (Adults and Children)

• 10 mg/kg IV at 2-week intervals for the first 3 doses and then at 4-week intervals thereafter.
• Infuse over 1 hour

Subcutaneous Dose of Belimumab for SLE (Adults)

• 200 mg SC once weekly.

Subcutaneous Dose of Belimumab for SLE (Child 5 years and older)

• Weight greater than or equal to 40 kg: 200 mg once weekly.
• Weight 15 kg to less than 40 kg: 200 mg once every 2 weeks.

Subcutaneous Dose of Belimumab for Lupus Nephritis (Adults)

• 400 mg (two 200 mg injections) once weekly for 4 doses, then 200 mg once weekly thereafter.

Subcutaneous Dose of Belimumab for Lupus Nephritis (Child 5 years and older)

• Weight greater than or equal to 40 kg: 400 mg ( two 200 mg injections) once weekly for 4 doses, followed by 200 mg once weekly.
• Weight 15 kg to less than 40 kg: 200 mg once weekly for 4 doses, followed by 200 mg once every 2 weeks.

Belimumab J Code

Belimumab J code is J0490 (Injection, Benlysta, 10 mg)

Belimumab is available as:

• Intravenous Infusion: belimumab lyophilized powder (120 mg or 400 mg) in a single-dose vial for reconstitution and dilution before intravenous infusion.
• Subcutaneous Injection: 200 mg/mL of belimumab in a single-dose prefilled autoinjector or single-dose prefilled syringe.

What happens if I miss a dose?

If you miss your dose of belimumab on your planned day, inject a dose as soon as you remember. Then, inject your next dose at your regularly scheduled time or continue dosing based on the new day of injection.

Do not use 2 injections on the same day. In case you are not sure when to inject belimumab, call your healthcare provider.

Call your doctor for instructions if you miss an appointment for an intravenous infusion of belimumab.

What happens if I overdose?

Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.

Belimumab Prescribing Information

Review the belimumab Prescribing Information or belimumab Package Insert for more detailed information about this medicine. Discuss any medical questions you have with your doctor or other health care provider. This is not all the information you need to know about this medicine for safe and effective use, and it does not take the place of talking to your doctor about your treatment.

What should I avoid while using belimumab?

Avoid being near people who are sick or have infections. Tell your doctor at once if you develop signs of infection.

Do not receive a "live" vaccine while using belimumab. The vaccine may not work as well and may not fully protect you from disease. Live vaccines include measles, mumps, rubella (MMR), rotavirus, typhoid, yellow fever, varicella (chickenpox), zoster (shingles), and the nasal flu (influenza) vaccine.

What other drugs will affect belimumab?

Other drugs may interact with belimumab, including prescription and over-the-counter medicines, vitamins, and herbal products. Tell your doctor about all your current medicines and any medicine you start or stop using.

Research does not support using belimumab with other biologic treatments, such as rituximab, in people with SLE because of the increased incidence of serious infections and post-injection systemic reactions.

Storage

Belimumab vials for intravenous infusion

Store belimumab vials for IV infusion in a refrigerator at 36°F to 46°F (2°C to 8°C). Store vials in the original carton until use to protect from light. Do not freeze. Avoid exposure to heat.

Belimumab autoinjectors and prefilled syringes for subcutaneous injection

Prior to dispensing and following dispensing. Refrigerate prefilled belimumab autoinjectors and prefilled syringes at 36°F to 46°F (2°C to 8°C). Keep the product in the original carton to protect it from light until the time of use. Do not freeze. Do not shake. Avoid exposure to heat.

Ingredients

Belimumab is only available as the brand name Benlysta.

Active ingredient: belimumab.

Benlysta inactive ingredients (intravenous): citric acid, polysorbate 80, sodium citrate, sucrose.

Benlysta inactive Ingredients (subcutaneous): L-arginine hydrochloride, L-histidine, L-histidine monohydrochloride, polysorbate 80, sodium chloride.

Manufacturer

GlaxoSmithKline LLC manufactures belimumab under the brand name Benlysta.

Belimumab Biosimilars

Biosimilar and interchangeable products are biological products that are highly similar to and have no clinically meaningful differences from the reference product.

Reference products

These are biological products that have already been approved by the FDA, against which biosimilar products are compared. There is 1 for belimumab.

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Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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