“…Lupus is an autoimmune disease characterized by inflammatory processes that can occur in various tissues and organs of the body� 1 A common form of lupus is systemic lupus erythematosus (SLE) 2 with an estimated prevalence of about 1 in 2,000 individuals in Canada� 3,4 The age of onset is primarily between 16 and 55 years, 5 with females more commonly affected than males (9:1)� 4 The median ages at diagnosis for white females range from 37 to 50 years, in white males from 50 to 59, in Black females from 15 to 44, and in Black males from 45 to 64� 5 Kidney injury is common in SLE, with lupus nephritis (LN) occurring in about 50% of patients with SLE, 6 usually within 5 years of SLE diagnosis� 7 Kidney involvement can remain silent or asymptomatic for a significant period of time; 8 however, patients may experience fatigue, joint and muscle pain, edema, rash, and a variety of other symptoms� 9 The disease is associated with substantial morbidity 6 as serious complications include progression to end-stage renal disease (ESRD), 10 in which patients require dialysis or kidney transplant� 8 Initial treatment options for induction of class III, IV, and/or V active LN include a high-dose corticosteroid taper as well as immunosuppressive drugs such as mycophenolate mofetil (or mycophenolic acid) or cyclophosphamide� 8,11 The clinical expert consulted by CADTH for this review noted that other treatments in addition to standard of care for patients with an inadequate response to first-line induction therapy may include off-label use of rituximab, cyclosporin, or tacrolimus� The clinical expert for this review stated that in all cases of class III, IV, and/or V active LN, use of antimalarials (i�e�, hydroxychloroquine), bone protection (vitamin D, calcium, possibly antiresorptive drugs), immunizations with nonlive vaccines, and adjunct treatment with renin-angiotensin blockade and statins should be considered� Belimumab inhibits the B lymphocyte stimulator protein and thus reduces B-cell activity� 12 The IV administration is 10 mg/kg, administered over an hour, at 2-week intervals for the first 3 doses and at 4-week intervals thereafter in addition to standard of care therapy for patients with active LN� The recommended dose for subcutaneous injection, in addition to standard of care therapy, is 400 mg (two 200 mg injections) once weekly for 4 doses, then 200 mg once weekly thereafter for the treatment of adult patients with active LN�…”