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Background: The REGENCY trial (NCT04221477) randomized adults with active lupus nephritis (LN) to placebo or obinutuzumab plus standard therapy (PBO+ST; OBI+ST). At Week 76 (W76), significantly more OBI+ST patients (pts) vs PBO+ST pts achieved complete renal response (CRR) (46.4% vs 33.1% adjusted difference 13.4%, 95% CI, 2.0% to 24.8%; P=0.0232). Evaluating histologic changes of paired baseline and W76 biopsies, we postulated that OBI+ST would yield greater rates of histologic remission at W76 than PBO+ST. Methods: Sixty-four (32 OBI+ST, 32 PBO+ST) blinded baseline and W76 biopsies were interpreted by Arkana Laboratories using 2018 ISN/RPS LN classification and NIH activity index (AI) and chronicity index. Proportions of pts achieving histologic or near-histologic remission (AI=0 or AI≤1) were determined. Results: Baseline characteristics were balanced and consistent with the overall REGENCY cohort (Table 1). Significantly more pts achieved AI≤1 or AI=0 with OBI+ST vs PBO+ST at W76 (Figure 1). For pts who did not achieve CRR, 52.6% (10/19) in the OBI+ST group had AI=0 at W76 vs 8.3% (2/24) in the PBO+ST group. Conclusion: In the largest longitudinal kidney biopsy cohort ever reported for a registrational LN clinical trial, significantly more pts treated with OBI+ST achieved complete and/or near-complete histologic remission vs PBO+ST. The higher proportion of pts achieving histologic remission vs CRR suggests that the impact of OBI in LN is greater than that implied by CRR rate. Achieving histologic remission reduces future LN flare risk and should preserve functional kidney mass. Funding: Commercial Support - F. Hoffmann-La Roche Ltd
Rovin et al. (Wed,) studied this question.