Obinutuzumab in LN: Phase III REGENCY trial exploratory analyses

Results from exploratory analyses of the phase III REGENCY (NCT04221477) trial evaluating obinutuzumab vs placebo in adults with lupus nephritis (LN) were presented by Richard A. Furie at the European Alliance of Associations for Rheumatology (EULAR) 2026 Congress, June 3–6, 2026, London, UK. The objectives of the analyses were to evaluate histologic remission and depletion of B cells and antibody-secreting cells after Week 76 in patients with available kidney biopsies (n = 32).

Key data: At Week 76, a greater proportion of patients receiving obinutuzumab achieved near-histologic (Activity Index [AI] ≤ 1; 65.6% vs 21.9%; p = 0.0002) or histologic (AI = 0; 46.9% vs 18.8%; p = 0.0111) remission vs placebo. Among patients who did not attain complete renal response (CRR), 52.6% vs 8.3% receiving obinutuzumab vs placebo achieved histologic remission (p = 0.0018). Obinutuzumab induced complete/near complete depletion of kidney B cells, with a median change from baseline of −98.34% vs +29.80% in patients receiving placebo, with median B-cell counts per mm² tissue of 0.31 vs 13.27 (p < 0.0001). Significantly greater reductions in kidney plasma cells were observed in the obinutuzumab group (−57.13%) vs the placebo group (+2.74%; p = 0.0039). 

Key learning: Obinutuzumab achieved greater histologic remission rates, including in CRR non-responders, and depleted kidney B cells, suggesting benefits beyond the conventional clinical endpoint of CRR in patients with LN.