Durable Renal Response and Safety with Add-on Belimumab in Patients with Lupus Nephritis in Real-Life Setting (Berliss-Ln). Results from a Large, Nationwide, Multicentric Cohort.

Background:LN is still a severe manifestation of Systemic lupus erythematosus (SLE) and multitarget therapy is needed to control the disease especially in refractory cases.Objectives:To evaluate renal response in SLE patients with glomerulonephritis (GN) treated with Belimumab in real-life setting.Methods:Patients with proteinuria >0.5 g/24 h and/or active sediment at baseline enrolled in a multicentre Italian cohort of SLE patients (BeRLiSS study), treated with monthly iv Belimumab 10 mg/kg plus standard of care were considered in this study. Complete renal response (CRR) was defined as proteinuria <0.5 g/24 h, estimated glomerular filtration rate (eGFR)≥90ml/min/1.73m2 and no rescue therapy. Primary efficacy renal response (PERR) was defined as proteinuria ≤0.7 g/24 h, eGFR ≥60ml/min/1.73m2 and no rescue therapy. Prevalence and predictive factors of CRR and PERR at 12 and 24 months after Belimumab initiation were analyzed by multivariate logistic regression analysis.Results:A total of 91 patients were considered in this study, 79 female, mean age 40.51±9.03 years, mean disease duration 12.18±8.15 years, median follow-up time after Belimumab initiation 22 months. Twenty patients had baseline proteinuria ≥0.5 <1 g/day, 17 ≥1 <2 g/day, 13 ≥2 g/day. Belimumab was started at GN onset in 20 (22%) patients and at the time of a renal flare in all other cases. Seventy-five patients underwent a renal biopsy: 1 class I, 4 class II, 14 class III, 47 class IV and 9 class V. Baseline serum creatinine was 82.44±29.26 umol/L; 15 patients showed eGFR<60ml/min/1.73m2 at baseline. Immunosuppresants were taken by 70 (76.9%) patients: 47 micofenolate, 15 azathioprine and 5 ciclosporine. Sixty patients (65.9%) were on antimalarials. During follow-up 34 (37.4%) patients achieved CRR. Among them 5 (14.7%) patients relapsed and 29 (85.3%) patients maintained remission. Mean time to achieved CRR was 9.71±5.91 months.High levels of baseline proteinuria were a negative independent predictor of CRR and PERR at 6 months (OR 0.044 CI95% 0.006-0.320 p=0.002 and OR 0.232 CI95% 0.091-0.596 p=0.002) and 12 months (OR 0.029 CI95% 0.002-0.556 p=0.019 and OR 0.056 CI95% 0.009-0.327 p=0.001). High levels of baseline creatinine were a negative independent predictor of renal response. Renal response at 6 months was a strong predictive factor of renal response at 12 and 24 months.Conclusion:Belimumab is an effective add-on therapy in the treatment of GN in real-life practice setting.Disclosure of Interests:None declared