P92 Quantifying the unmet need in lupus nephritis: EULAR/ERA- EDTA treatment targets, flares, and treatment modifications in the first year in a multicenter observational study

Objective To decide on the optimal positioning of combination therapies in lupus nephritis (LN), we aimed to determine renal response rates with standard-of-care (SoC) treatment at 3, 6 and 12 months according to EULAR/ERA- EDTA treatment targets in real-life clinical practice. Methods 135 patients with recent LN (2015- present) were included in a retrospective/prospective cohort study. Demographic, clinical, and laboratory data, as well as treatment at baseline and every 3 months were collected. Response rates in the first year according to EULAR/ERA-EDTA, flares, and use of glucocorticoids were calculated. Uni- and multivariate regression analysis was performed to assess determinants of renal flares during follow-up. Results 135 patients were included, of whom 107 completed a 12-month follow-up 82.2% female, median (IQR) age 38 (22), 35.5% with nephrotic range proteinuria at diagnosis. Histologically, 13.6% had class III, 36.4% class IV, 18.9% class V, and 28% mixed class LN (III/IV +V). With SoC therapy initial treatment 54.1% cyclophosphamide (CYC), (9.8% received Euro-Lupus), 30.1% mycophenolic acid (MPA), followed by maintenance, 73%, 82.9% and 84.4% achieved EULAR/ERA-EDTA renal response rates at 3, 6 and 12 months, respectively. Patients treated with CYC differed significantly in histological parameters compared to MPA (table 1). All patients received IV methylprednisolone at baseline median (IQR) 2.0 (2.0) gr. In class IV LN, median (IQR) daily prednisone starting dose was 50.0 (20.0) mg/day, and at 6 months 10.0 (10.0) mg. In class III and V LN, median (IQR) daily starting doses were lower, 40.0 (32.0) mg and 30.0 (25.0), respectively, whereas at 6 months median (IQR) doses were equal, 10.0 (15) mg and 10.0 (7.5), respectively. 22 (20%) patients experienced a flare during the first 12 months of follow-up; 4 (18.2%) and 7 (31.8%) patients were added or switched to a different immunosuppressive drug, respectively. Level of proteinuria at baseline was associated with increased risk for flare in univariate analysis (OR 1.18, p=0.025). Conclusions Although the majority of LN patients achieve a complete response by 12 months, a considerable proportion experience flares that necessitate treatment modification to reach this target.