• Systemic Lupus Erythematosus (SLE) – seropositive, active autoantibody-positive SLE (ages ≥5 years)
  • Lupus Nephritis – adults and children ≥5 years, in combination with standard therapy
  • Off-label/Investigational: Sjögren’s syndrome, other autoantibody-mediated disorders (under study)

Dosage:

  • Adults (IV):10 mg/kg IV at 0, 2, and 4 weeks, then every 4 weeks,Infuse over 1 hour

  • Adults (SC):200 mg SC once weekly

  • Pediatrics (≥5 years, IV only):10 mg/kg IV at same schedule as adults

For lupus nephritis, belimumab is used alongside steroids and immunosuppressants like mycophenolate or cyclophosphamide.

  • IV formulation: 120 mg or 400 mg lyophilized vials
  • SC prefilled syringe/auto-injector: 200 mg/mL
  • IV: Reconstitute and dilute in NS; administer over 1 hour
  • SC: Administer into abdomen or thigh
  • Do not shake vials or auto-injectors
  • Refrigerate; allow to reach room temp before injection
  • Class: Human IgG1-λ monoclonal antibody
  • Mechanism of Action:
    • Binds BLyS (B-lymphocyte stimulator) → inhibits survival of autoreactive B cells → ↓ autoantibody production
  • Half-life: ~19 days
  • Onset of effect: ~8–16 weeks
  • Excretion: Not fully understood (IgG metabolism)
  • Nausea
  • Diarrhea
  • Fever
  • Insomnia
  • Headache
  • Injection site reactions
  • Arthralgia
  • Previous anaphylaxis to belimumab
  • Live vaccines should be avoided during and for a period after therapy

Use caution in active infections, severe depression, or immunosuppression

    • No major CYP interactions
    • Avoid live vaccines (risk of infection)
    • Additive immunosuppression when combined with:
      • Steroids
      • Cytotoxic agents (e.g., azathioprine, mycophenolate)
  • Biologics (avoid combining with rituximab unless necessary)

                                   Drug Status

Availability
Pregnancy
Breastfeeding
Schedule
BRAND NAME STRENGTH FORMULATION PACK SIZE MANUFACTURER DISTRIBUTOR
Benlysta 120mg Injection 1’s GSK Ltd GSK Ltd