Clinical outcomes of anifrolumab after belimumab failure in systemic lupus erythematosus: A single-center case series

Objectives To describe clinical outcomes after switching to anifrolumab in patients with systemic lupus erythematosus (SLE) who showed inadequate response to belimumab, and to explore clinical features potentially associated with treatment response in real-world settings. Methods We retrospectively reviewed the cases of eight patients with SLE who were switched from belimumab to anifrolumab because of insufficient clinical response. Clinical data, including the SLE Disease Activity Index 2000 (SLEDAI-2K), serological markers, organ involvement, medication use, and attainment of a lupus low disease activity state (LLDAS), were descriptively evaluated. Results All eight patients were female; most were young and had active mucocutaneous manifestations. Three patients presented with cutaneous vasculitis and one with panniculitis. Three patients had neuropsychiatric manifestations, including mood disorders or cerebrovascular disease, and one patient had membranous lupus nephritis. Following anifrolumab initiation, clinical improvement was observed predominantly in skin and neuropsychiatric manifestations, whereas renal involvement showed limited improvement. Improvements in SLEDAI-2K scores, complement levels, and glucocorticoid dose reduction were observed in most patients. Five patients achieved LLDAS during follow-up. Clinical improvement was more frequently observed among younger patients and those with active skin manifestations and anti-ribonucleoprotein antibody positivity. Conclusions In this exploratory case series, switching from belimumab to anifrolumab was associated with clinical improvement among selected patients with SLE. Certain clinical features, including active skin or neuropsychiatric manifestations and anti-ribonucleoprotein antibody positivity, were more frequently observed among patients who showed improvement after switching therapy. These findings should be interpreted as hypothesis-generating and warrant confirmation in larger prospective studies.