MO1014PROSPECTIVE STUDY OF SAFETY AND EFFECTIVENESS OF OFATUMUMAB AS A TREATMENT IN REFRACTORY NEPHROTIC SYNDROME (CORTICODEPENDENT AND CORTICORRESISTANT)

Abstract Background and Aims Ofatumumab (OFA) is an anti-CD-20 monoclonal antibody useful in nephrotic syndrome refractory to conventional treatments and rituximab (RTX). Our objective is to evaluate the response and safety in patients with nephrotic syndrome (NS) treated with Ofatumumab. Method A prospective descriptive study of 2 years duration (2017-2019) in children with NS refractory to first-line therapies who received treatment with anti-CD20 monoclonal antibodies. To do this, we divided the cohort into 3 groups: Patients with corticodependent NS (CDNS) without response or with adverse effects associated with first-line treatment that preclude its use (Group 1); Corticosteroid-resistant SN (CRNS) (Group 2) and SN with post-transplant recurrence (Group 3). In them, the results of safety and remission rate were evaluated. Results Thirty-three patients (21 with SNCD, 11 with SNCR, and 1 with SN recurrence in transplantation) were included and administered anti-CD20. The male / female ratio was 2: 1 and the mean age at diagnosis was 5.2 years. 100% of the children (33) received RTX and 18.2% (6) OFA. The RTX achieved complete remission in 87.9% (29) and 48.3% of these did not present new relapses after 70 months of follow-up. 100% of Group 1 presented complete remission after RTX, although 52.4% (11) presented at least 1 relapse after 22.9 months (mean 2.5 relapses). In group 2, 72.72% (8) complete remission and 27.2% (3) partial, with persistent proteinuria. 36.4% (4) presented relapse after 17 months of treatment (mean 1 relapse). Of the 6 who received OFA, 83.3% presented complete remission (1 SNCR and 4 SNCD) and 1 patient (SNCD) presented relapse at 24 months (mean follow-up 1 year). The other case, a 13-year-old girl with recurrence of focal segmental glomerulosclerosis (FSGS) in kidney transplantation, presented partial remission after one year of treatment in association with immunoadsorption sessions. Regarding safety, adverse reactions occurred in 6% (2): allergic reaction with 2nd dose of RTX and cytokine release syndrome with 1st dose of OFA. Conclusion Ofatumumab in our series has proven to be an effective and safe drug in difficult-to-manage NS, achieving complete remission in 5 patients who had not previously responded to Rituximab