WCN25-318 FELZARTAMAB DURABLY REDUCES DISEASE RELEVANT BIOMARKERS THROUGH TARGETING OF CD38+ PLASMA CELLS AND PLASMABLASTS, THE UPSTREAM DRIVERS OF IgA NEPHROPATHY (IgAN)

We enrolled 84 patients, 30 (36%) males and 54 (64%) females.Median age at AAV onset was 49.5 (35; 57) years.Seventy-four (88%) patients were ANCA-positive.Seventeen (20%) patients were diagnosed with renal-limited AAV.Median Birmingham vasculitis activity score (BVAS v.3) at biopsy was 14.5 (12; 18).Median follow-up after kidney biopsy was 16.5 (8.0; 48.7) months.According to the Berden et al classification 15 (18%) patients had focal, 17 (20%) had crescentic, 34 (40%) had mixed and 18 (21%) had sclerotic class.According to the ARRS 20 (24%) patients were classified as low-risk, 36 (43%) as moderate-risk, and 28 (33.3%) as high-risk.They were retrospectively reevaluated using AKRiS as follows: 30 (36%) -low-risk, 35 (42%)moderate-risk, 12 (14%)high-risk, and 7 (8%)very high risk.Nineteen (23%) patients developed end-stage kidney disease.All three prognostication models showed statistically significant differences in kidney survival (Fig. 1), however histopathologic classification demonstrated a significantly lower predictive ability (Harrel's C0.651, 95% CI 0.514-0.788)compared to ARRS (C0.839,95% CI 0.785-0.894,p0.012) and AKRiS (C0.861,95% CI 0.787-0.936,p0.019).Conclusions: In our single center cohort, all three prognostication tools showed their ability to predict kidney outcomes in patients with ANCA-GN, therefore they all can be used to personalize treatment.However, ARRS and its updated version AKRiS demonstrated a significantly better prognostication ability compared to the histopathologic classification by Berden et al.I have no potential conflict of interest to disclose.I did not use generative AI and AI-assisted technologies in the writing process.