First experience with obinutuzumab in a juvenile-onset systemic lupus erythematosus patient with rituximab-associated posterior reversible encephalopathy syndrome

Juvenile-onset systemic lupus erythematosus (JSLE) is characterized by higher disease activity and greater treatment burden than adult-onset disease, often requiring intensive immunosuppression. Rituximab is used in refractory cases, but re-exposure may not be possible when adverse events such as posterior reversible encephalopathy syndrome (PRES) occur. Obinutuzumab, a type II anti-CD20 monoclonal antibody, has shown efficacy in adult patients with lupus nephritis and in those with active SLE, yet pediatric experience is limited. We report an 11-year-old boy with JSLE and lupus nephritis who developed lupus pneumonitis and increased renal activity while receiving conventional therapy. Rituximab was initiated but complicated by PRES six hours after the first infusion, leading to discontinuation. Despite cyclophosphamide induction and mycophenolate mofetil plus cyclosporine maintenance, he later experienced a disease flare with malar rash, low complement levels, and rising anti-dsDNA titres. Because rituximab re-use was avoided, obinutuzumab was selected as an alternative anti-CD20 agent in the setting of a disease flare. A body-surface-area-adjusted regimen derived from the adult protocol was administered in two infusions under close monitoring. Following obinutuzumab, complement levels normalized, anti-dsDNA declined, and SLEDAI-2K decreased from 6 to 2, and peripheral B-cell depletion was confirmed at eight weeks and maintained at six months, without neurological or infectious complications over six months of follow-up. This case suggests that obinutuzumab may be a feasible alternative anti-CD20 option in rituximab-intolerant JSLE, pending results from ongoing pediatric clinical trials.