belimumab at a glance
Medicine class
B-cell-targeted monoclonal antibody and immunosuppressant
Licensed roles
Add-on treatment for selected people with active systemic lupus erythematosus, and for adults with active lupus nephritis
How it is given
By injection under the skin using a pre-filled pen, or by intravenous infusion administered by a healthcare professional
Key precautions
Infections, severe allergic reactions, mood changes and live vaccines require particular attention
What is belimumab used for?
Licensed uses represented by the selected products are:
Add-on therapy for people aged 5 years and over with active, autoantibody-positive systemic lupus erythematosus and high disease activity despite standard therapy.
Treatment of active lupus nephritis in adults alongside background immunosuppressive therapies.
How does belimumab work?
Belimumab blocks soluble B-lymphocyte stimulator, also called BLyS or BAFF. This reduces the survival of B cells, including autoreactive B cells, and their development into antibody-producing plasma cells, helping reduce lupus immune activity.
belimumab preparations and strengths
Solution for infusion
Route: Intravenous
Strengths: 120 mg, 400 mg
Injection
Route: Parenteral
Strengths: 200 mg
How to take belimumab
Intravenous treatment is prepared and administered by trained healthcare professionals where severe infusion reactions can be managed. A pre-filled pen may be used at home only after appropriate training and initial supervision.
Inject under the skin of the abdomen or thigh; rotate sites and avoid tender, bruised, red or hard skin.
Allow the pen to reach room temperature naturally. Do not shake it or use heat, hot water or a microwave.
Check that the solution is colourless to slightly yellow and is not cloudy or particulate.
Use each pen once and dispose of it in an appropriate sharps container.
belimumab side effects
Common or expected effects
- Infections such as bronchitis, urinary tract infection, sore throat or upper respiratory infection
- Nausea or diarrhoea
- Migraine or headache
- Fever or pain in an arm or leg
- Rash, hives or an injection-site reaction
- Reduced white blood cell count
- Depression
- Infusion- or injection-related symptoms
Get urgent medical advice
- Severe or delayed allergic reaction, including anaphylaxis
- Serious or opportunistic infection
- New or worsening depression, suicidal thoughts or self-harm behaviour
- Stevens–Johnson syndrome or toxic epidermal necrolysis
- New neurological, cognitive or psychiatric symptoms suggesting progressive multifocal leukoencephalopathy
belimumab in pregnancy
Pregnancy data are limited. Product information advises use only when the potential benefit justifies the potential fetal risk and recommends effective contraception during treatment and afterwards. Specialist use may be considered for severe disease when suitable alternatives are unavailable. Later-pregnancy exposure may affect decisions about live vaccines for the infant.
belimumab while breastfeeding
Transfer into human milk and absorption by the infant are uncertain, so the benefits of breastfeeding and maternal treatment should be weighed together. Specialist guidance considers belimumab compatible with breastfeeding on limited evidence; discuss the individual situation with the rheumatology and maternity teams.
belimumab interactions
Formal interaction studies are limited. Important practical considerations include:
Live vaccines
Avoid shortly before and during treatment because safety is not established and the immune response may be altered.
Rituximab and other B-cell-targeted therapies
Combined use is not supported by available evidence and may add immunosuppressive risk; specialist caution is required.
Common questions about belimumab
Answers are fully visible for fast scanning and source review.
Is belimumab a steroid?
No. It is a biologic monoclonal antibody that blocks the B-cell survival signal BLyS/BAFF.
Is belimumab an immunosuppressant?
Yes. It modifies B-cell survival and can increase susceptibility to infection, although it does not bind directly to B cells.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.