Efficacy and safety of rituximab in children with difficult-to-treat nephrotic syndrome

Background. Rituximab has emerged as an important medication for patients with steroid-dependent or steroid-resistant nephrotic syndrome. Patients. We report the efficacy and safety of therapy with intravenous rituximab, administered once weekly for 2-4 doses, in 193 patients (mean age 10.9, range 2.2-18.7 years) with difficult-to-treat steroid dependence (n = 101), calcineurin inhibitor (CNI)-dependent steroid resistance (n = 34) and CNI-resistant nephrotic syndrome (n = 58) managed at this center during 2006-13. Outcomes. Therapy in patients with steroid dependence and CNI-dependent steroid resistance led to significantly reduced relapse rates (respective mean difference 2.7 relapses/year and 2.2 relapses/year, corresponding to a decrease in relapses by 81.8 and 71.0%; both P < 0.0001). This resulted in a significant reduction in steroid requirement (mean difference 104.5 and 113.6 mg/kg/year, respectively; both P < 0.0001) and a trend to improved standard deviation scores for height (P = 0.069) and body mass index (P = 0.029). Remission was longer in patients with steroid dependence compared with CNI-dependent steroid resistance (median 16 versus 10 months; P < 0.0001). Prior response to cyclophosphamide predicted a lower risk of relapse in the former (hazard ratio, HR 0.56; P = 0.045); patients with initial resistance and CNI-dependent steroid resistance had increased risk of relapse (HR 2.66; P = 0.042). B-cell recovery, noted in 62.5% patients at 6 months, was not related to occurrence of relapse; redosing (n = 42 patients) was safe and effective. Response to therapy was unsatisfactory in patients with steroid-and CNI-resistant nephrotic syndrome, with remission in 29.3%. Focal segmental glomerulosclerosis was associated with higher odds of non-response (odds ratio 11.1; P = 0.028) and lack of response was associated with progressive chronic kidney disease (HR 9.97; P = 0.035). Therapy with rituximab was safe; adverse effects or infections were noted in 19 (9.8%) patients. Conclusions. Therapy with rituximab is effective and safe in reducing relapse rates and need for immunosuppressive medications in patients with steroid-dependent and CNI-dependent steroid-resistant nephrotic syndrome.