Low-dose ofatumumab for rituximab-resistant nephrotic syndrome.

Drug resistant idiopathic nephrotic syndrome (DRNS) remains a therapeutic dilemma. In this pilot study, the efficacy of the new fully humanised, anti-CD20 monoclonal antibody ofatumumab was tested in 4 children with persistence of proteinuria for at least 12 months in spite of a full drug approach (including rituximab). We used a low-dose 2-infusion ofatumumab model (300+700 mg/1.73 m(2) 2 weeks apart) using specified premedication. Transient normalisation of proteinuria (persisting for 2 months) was achieved in 1 child while another presented stable remission after 12 months; both had normal renal function. The outcome was not modified in the remaining 2 children presenting an impaired renal function. These results demonstrate that low-dose ofatumumab may induce remittance of proteinuria in children with a long story of DRNS and normal renal function. Further studies are needed to test whether higher doses of ofatumumab can also modify proteinuria in patients with impaired renal function. 2015 BMJ Publishing Group Ltd.