Obinutuzumab in Frequently Relapsing and Steroid-Dependent Nephrotic Syndrome in Children.

BACKGROUND: B-cell depletion with rituximab induces sustained remission in children with steroid-dependent or frequently relapsing nephrotic syndrome. However, most patients relapse after B-cell recovery, and some patients do not achieve B-cell depletion. Obinutuzumab is a second-generation anti-CD20 antibody designed to overcome such situations in B-cell malignancies and was recently reported to be safe and effective in other autoimmune diseases affecting the kidneys. METHODS: We retrospectively report 41 children with steroid-dependent or frequently relapsing nephrotic syndrome treated with a single low-dose infusion of obinutuzumab at Robert-Debre Hospital between April 2018 and December 2020. Participants were treated because of rituximab resistance or relapse after rituximab and received a single infusion of 300 mg/1.73 m 2 obinutuzumab with cessation of oral immunosuppressors within 2 months. RESULTS: B-cell depletion was achieved in all participants and lasted a median of 8.3 months (interquartile range, 6.4-11.1), a duration exceeding that for last rituximab treatment. At 12 and 24 months, 92% (38/41) and 68% (28/41) of patients, respectively, were in sustained remission. Mild infusion reactions occurred in five participants (12%) and neutropenia in nine (21%). No significant decrease in IgG level was reported during treatment, and whereas IgM levels decreased in 34 patients (83%), they were normal at last follow-up in 32 (78%). CONCLUSIONS: These results identified low-dose obinituzumab as a promising treatment option in children with steroid-dependent or frequently relapsing nephrotic syndrome, including those resistant to rituximab. The tolerance profile of obinutuzumab was similar to that of rituximab, but hemogram and immunoglobulin levels should be monitored.

A global antiB cell strategy combining obinutuzumab and daratumumab in severe pediatric nephrotic syndrome.

BACKGROUND: Steroid-sensitive nephrotic syndrome (SSNS) is, in most patients, a chronic disease with 80% experiencing at least one relapse after first flare. B cell depletion using rituximab is effective in preventing relapse in steroid-dependent (SDNS) patients but fails to maintain long-term remission following B cell recovery, possibly due to development of autoreactive long-lived plasma cells. We investigated sequential combination of antiCD20 antibody targeting all B cell subsets, and antiCD38 antibody with high plasma cell cytotoxicity in patients with uncontrolled SDNS after failure of one or several attempts at B cell depletion. METHODS: Fourteen patients with median disease duration 7.8 years received 1000 mg/1.73 m2 obinutuzumab followed by 1000 mg/1.73 m2 daratumumab 2 weeks later. Oral immunosuppression was discontinued within 6 weeks, and biological monitoring performed monthly until B cell recovery. RESULTS: Median age at treatment was 11.0 [IQR 10.4-14.4] years. B cell depletion was achieved in all patients, and B cell reconstitution occurred in all at median 9.5 months after obinutuzumab injection. After median follow-up 20.3 months (IQR 11.5-22.6), 5/14 patients relapsed including 4 within 100 days following B cell repletion. Relapse-free survival was 60% at 24 months from obinutuzumab infusion. Mild infusion reactions were reported in 3/14 patients during obinutuzumab and 4/14 during daratumumab infusions. Mild transient neutropenia (500-1000/mm3) occurred in 2/14 patients. Intravenous immunoglobulins were given to 12/14 patients due to hypogammaglobulinemia. Low IgA and IgM levels were noted in 8 and 14 patients, respectively. No severe infection was reported. CONCLUSION: Global antiB cell strategy combining obinutuzumab and daratumumab induces prolonged peripheral B cell depletion and remission in children with difficult-to-treat SDNS.