Efficacy and Safety of Obinutuzumab in Active Lupus Nephritis

BACKGROUND: Obinutuzumab, a humanized type II anti-CD20 monoclonal antibody, provided significantly better renal responses than placebo in a phase 2 trial involving patients with lupus nephritis receiving standard therapy. METHODS: In a phase 3, randomized, controlled trial, we assigned adults with biopsy-proven active lupus nephritis in a 1:1 ratio to receive obinutuzumab in one of two dose schedules (1000 mg on day 1 and at weeks 2, 24, 26, and 52, with or without a dose at week 50) or placebo. All patients received standard therapy with mycophenolate mofetil, along with oral prednisone at a target dose of 7.5 mg per day by week 12 and 5 mg per day by week 24. The primary end point was a complete renal response at week 76, defined by a urinary protein-to-creatinine ratio of less than 0.5 (with protein and creatinine both measured in milligrams), an estimated glomerular filtration rate of at least 85% of the baseline value, and no intercurrent event (i.e., rescue therapy, treatment failure, death, or early trial withdrawal). Key secondary end points at week 76 included a complete renal response with a prednisone dose of 7.5 mg per day or lower between weeks 64 and 76 and a urinary protein-to-creatinine ratio lower than 0.8 without an intercurrent event. RESULTS: A total of 271 patients underwent randomization; 135 were assigned to the obinutuzumab group (combined dose schedules) and 136 to the placebo group. A complete renal response at week 76 was observed in 46.4% of the patients in the obinutuzumab group and 33.1% of those in the placebo group (adjusted difference, 13.4 percentage points; 95% confidence interval [CI], 2.0 to 24.8; P = 0.02). A complete renal response at week 76 with a prednisone dose of 7.5 mg per day or lower between weeks 64 and 76 was observed in more patients in the obinutuzumab group than in the placebo group (42.7% vs. 30.9%; adjusted difference, 11.9 percentage points; 95% CI, 0.6 to 23.2; P = 0.04), and a urinary protein-to-creatinine ratio lower than 0.8 without an intercurrent event was more common with obinutuzumab than with placebo (55.5% vs. 41.9%; adjusted difference, 13.7 percentage points; 95% CI, 2.0 to 25.4; P = 0.02). No unexpected safety signals were identified. More serious adverse events, mainly infections and events related to coronavirus disease 2019, occurred with obinutuzumab than with placebo. CONCLUSIONS: Among adults with active lupus nephritis, obinutuzumab plus standard therapy was more efficacious than standard therapy alone in providing a complete renal response. (Funded by F. Hoffmann-La Roche; REGENCY ClinicalTrials.gov number, NCT04221477.).