Re-treatment with high-dose prednisolone after rituximab infusion for childhood-onset steroid-resistant nephrotic syndrome

Rituximab therapy for refractory steroid-resistant nephrotic syndrome in children

Patients with steroid-resistant nephrotic syndrome (SRNS) who develop resistance to immunosuppressive agents, defined as refractory SRNS, have poor renal outcomes. Although the chimeric anti-CD20 monoclonal antibody rituximab has shown efficacy for frequently relapsing nephrotic syndrome and steroid-dependent nephrotic syndrome, its efficacy for refractory SRNS remains uncertain due to limited data. According to previous case reports, 50.4% of patients with refractory SRNS showed clinical improvements after rituximab treatment. Remission rates in patients with initial steroid resistance and late steroid resistance were 43.9 and 57.7%, respectively, and 41.5 and 63.6% in patients with focal segmental glomerulosclerosis and minor glomerular abnormalities, respectively. However, various factors (race, disease severity, number of rituximab doses, concomitant treatments, and observation period) differed among these observational studies and their consensus may also have been affected by potential publication bias. Rituximab monotherapy may have some degree of efficacy and lead to satisfactory outcomes in a subset of patients with refractory SRNS. However, administration of concomitant treatments during rituximab-mediated B cell depletion, such as methylprednisolone pulse therapy, daily oral prednisolone therapy, and immunosuppressive agents, may lead to better outcomes in these patients. Large-scale, multi-center prospective studies are needed to evaluate the efficacy and safety of such regimens.

Rituximab Use in the Management of Childhood Nephrotic Syndrome

Childhood nephrotic syndrome is a challenging and often persistent renal disorder, and its incidence varies between different ethnicities and regions. Corticosteroids have been the main treatment for decades and are effective in most children with idiopathic NS, although 10-15% of these children become steroid resistant. Furthermore, some initially steroid sensitive children follow a steroid dependent or frequently relapsing course and are therefore at increased risk for developing steroid toxicity. In such children, alternative immunosuppressive medications are used to induce and/or maintain remission of NS. One such drug, rituximab, is a monoclonal antibody directed against the B lymphocyte CD20 marker which induces depletion of B cells, and has shown promising results in the management of NS in children. In this review, we summarize recent studies on the efficacy and safety of rituximab in the different types of childhood nephrotic syndrome, the known and potential mechanisms of action of rituximab, its possible complications and side effects, and the available and potential biomarkers of rituximab activity.