Written by Kevin Liu
Spoon Feed
The addition of obinutuzumab as an adjunct to standard treatment for lupus nephritis resulted in significantly more complete renal recovery but higher risk of infection.
Obinutuzumab: B-cell depletion like a pro, but watch out for immunosuppression
Lupus nephritis is a feared complication of systemic lupus erythematous (SLE), the end of a cascade of immune complex deposition in glomeruli, complement cascade activation, dysregulated B/T cell responses, and chronic inflammation leading to glomerular damage and renal fibrosis.
This phase 3, randomized, double-blind, placebo-controlled trial evaluated the efficacy and safety of obinutuzumab, a humanized glycoengineered type II anti-CD20 monoclonal antibody in the treatment of active lupus nephritis. The primary endpoint was a complete renal response at week 76, defined by a urinary protein-to-creatinine ratio <0.5, estimated glomerular filtration rate (eGFR) 85% of baseline, and no intercurrent events. The obinutuzumab group achieved a significantly higher complete renal response (46.4%) compared to placebo (33.1%): adjusted difference 13.4% (95%CI 2.0–24.8; P = 0.02, NNT = 7.5). Secondary outcomes included a complete renal response with prednisone ≤7.5 mg/day (42.7% vs. 30.9%; P = 0.04) and a urinary protein-to-creatinine ratio <0.8 (55.5% vs. 41.9%; P = 0.02).
Infusion reactions and neutropenia were more frequent with obinutuzumab. Serious adverse events occurred in 32.4% (drug( vs. 18.2% (placebo). Four deaths occurred, three in the obinutuzumab group (two from COVID-19 pneumonia) and one in the placebo group (COVID-19 pneumonia).
How does this change my practice?
As a hospitalist, I will never prescribe obinutuzumab inpatient, but I have seen many patients who are on half a dozen biologics and immunomodulating drugs experience progressive nephritis despite treatment. As the newest and most potent anti-CD20 on market, obinutuzumab eliminates B-cell response to halt the inflammatory cascade at the cost of knocking out humoral immunity. The risk/benefits are roughly equal with ~13% absolute risk reduction in lupus nephritis over a 76 week period and also a ~14% absolute risk increase for severe adverse effects largely due to infection. Starting obinutuzumab warrants a thoughtful conversation and maybe one that includes prophylactic antibiotics, which is what we offer another group of humoral immunodeficient patients, asplenic patients.
Source
Efficacy and Safety of Obinutuzumab in Active Lupus Nephritis. N Engl J Med. 2025 Feb 7. doi: 10.1056/NEJMoa2410965. Epub ahead of print. PMID: 39927615
