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Antibody Drug Stabilizes Kidney Function in 510 Adults With IgA Nephropathy

A monoclonal antibody aimed at a kidney-damaging immune pathway kept kidney function stable over two years in a major trial.

By Dr. Josh Axe · November 1, 2026 · 1 source · Watch

Photo: Pexels

A monoclonal antibody called sibeprenlimab kept kidney function essentially flat over two years in adults with IgA nephropathy, according to final results from the Sibeprenlimab in IgA Nephropathy — Final Phase 3 Trial Analysis published October 22, 2026 in the New England Journal of Medicine.

IgA nephropathy is a kidney disease in which antibody deposits build up in the kidney's filtering units and gradually destroy them. In this trial, 510 adults were randomly assigned to receive sibeprenlimab at 400 mg, or a placebo injection, every 4 weeks for 24 months.

The key measure was eGFR, a blood test estimating how well the kidneys filter waste. Over 24 months, the annual eGFR slope was +0.3 ml per minute per 1.73 square meters with sibeprenlimab versus -4.2 with placebo, a difference of 4.5 points a year. From baseline to 24 months, eGFR changed by 9.2 points more in the drug group. A composite outcome of kidney-function decline or kidney failure occurred in 1 of 259 patients (0.4%) on sibeprenlimab versus 28 of 251 patients (11.2%) on placebo. Adverse events occurred in 235 of 259 patients (90.7%) on the drug and 226 of 251 patients (90.0%) on placebo; serious adverse events affected 21 patients (8.1%) versus 32 patients (12.7%); serious infections affected 5 patients (1.9%) versus 10 patients (4.0%). No deaths were reported in either group.

APRIL is an immune signal the authors call a key driver of IgA nephropathy. By blocking it, sibeprenlimab kept the eGFR slope essentially flat for two years, which the authors say is consistent with a reduced risk of kidney-function decline.

Annual Kidney Function Change Over 24 Months

New England Journal of Medicine, 2026, Rizk et al.

This trial ran 24 months; whether the stabilized kidney function holds up over many more years, and whether it translates into fewer dialysis starts or transplants, has not been shown here.

Dr. Axe’s Take

This is a big result for a kidney disease that usually marches toward dialysis. My question is why the immune system keeps making these deposits. In general, IgA nephropathy is thought to start with immune triggers in the gut and airway linings, which this trial didn't test, and a shot every four weeks doesn't touch that. The cost is a drug you stay on, and APRIL also keeps antibody-making cells alive, so lower antibody levels come with it. Serious infections weren't higher over two years; that's what I'd watch long term. And listen, never stop or change a medication on your own. Make that change with your practitioner.

— Dr. Axe

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Study summary

Who: 510 adults with IgA nephropathy; 259 received sibeprenlimab, 251 received placebo.
Design: Phase 3 randomized, placebo-controlled trial, 24 months.
Dose: Sibeprenlimab 400 mg or placebo, both subcutaneous, every 4 weeks.
Primary result: Annualized eGFR slope: +0.3 vs -4.2 ml/min/1.73m2/year (difference 4.5); eGFR change at 24 months 9.2 points greater with sibeprenlimab.
Secondary: Kidney decline/failure composite: 0.4% (1/259) with sibeprenlimab vs 11.2% (28/251) with placebo. Serious adverse events: 8.1% with sibeprenlimab vs 12.7% with placebo. Serious infections: 1.9% with sibeprenlimab vs 4.0% with placebo. No deaths reported.
Funding / conflicts: Funded by Otsuka Pharmaceutical Development and Commercialization. ClinicalTrials registry number NCT05248646.
Date: Oct 22, 2026