Anti-BLyS Monoclonal Antibody (B-cell Inhibitor)

Belimumab

Brand names: Benlysta

Belimumab is a monoclonal antibody used as add-on therapy in active autoantibody-positive systemic lupus erythematosus and in lupus nephritis.

Dosing — being independently re-sourced

ClinCalc Pro is rebuilding its dose data from primary open sources — the manufacturer SmPC (eMC), the WHO Model Formulary and other official references — under clinician review. This drug's structured dose is not yet published here. Confirm all doses against the product SmPC and your local formulary before prescribing.

Clinical monograph

How it works

It binds and inhibits B-lymphocyte stimulator (BLyS/BAFF), reducing the survival and activity of autoreactive B cells that contribute to lupus.

Prescribing in practice

Serious infections can occur and treatment should not be started during an active severe infection; hypersensitivity and infusion or injection reactions are also recognised.
It is given by intravenous infusion or subcutaneous injection as add-on therapy to standard treatment.
It has not been studied in severe active central nervous system lupus, and psychiatric events including depression have been reported.

Monitoring

Monitor for infections, hypersensitivity and new or worsening mood or psychiatric symptoms during treatment.

Counselling the patient

Report signs of infection and any new low mood or thoughts of self-harm promptly.
Avoid live vaccines during treatment.

Evidence & guidelines

Belimumab is recommended by NICE as an add-on option in active autoantibody-positive systemic lupus erythematosus on the basis of its trial evidence.

Reference: NICE TA397; BLISS trials; Drug verified in RxNorm (NLM); confirm dosing against the manufacturer SPC (eMC). Verify against your local formulary and current prescribing references before prescribing. Monograph status: clinician-reviewed (2026-07-04).

Curated clinical cross-links plus same-class fallbacks.

Calculators

Pathways