(Vienna, Austria, Thursday 5 June 2025) New 100-week data from the ongoing Phase 1/2 study of zigakibart, an investigational anti-APRIL monoclonal antibody, reinforce its potential as a disease-modifying treatment for IgA nephropathy (IgAN). Findings presented today at the 62nd ERA Congress demonstrate sustained proteinuria remission, stable kidney function, and a reassuring safety profile.1
IgAN is the most common form of glomerular disease worldwide and a frequent cause of chronic kidney disease. Its pathogenesis is marked by inflammation and progressive kidney damage, which can lead to kidney failure.² Many patients are unaware they have the condition until significant kidney damage has occurred, and 50% of IgAN patients will ultimately develop kidney failure as a result of the disease.3
By targeting the APRIL pathway and reducing production of pathogenic galactose-deficient IgA1 (Gd-IgA1), zigakibart addresses a key driver of disease progression.4 “Zigakibart is designed to intercept the initiating factor in IgAN pathogenesis, offering a new approach that may halt or significantly delay progression,” explained lead investigator Professor Jonathan Barratt.6
The ADU-CL-19 trial included 40 adults with biopsy-confirmed IgAN and persistent proteinuria despite stable supportive therapy. Patients received zigakibart every two weeks via intravenous infusion or subcutaneous injection, in addition to maximally tolerated renin–angiotensin system inhibitors (RASi) unless RASi-intolerant – demonstrating efficacy beyond standard care.
At Week 100, proteinuria was reduced by 60% from baseline. Over half of patients (55%) reached <500 mg/24 h, and 31% achieved <300 mg/24 h, indicating deeper remission. Estimated glomerular filtration rate (eGFR) remained stable across subgroups. “The consistency of eGFR stabilisation over 100 weeks, even across proteinuria response groups, is a particularly encouraging finding,” said Prof. Barratt.
Treatment also led to sustained reductions in serum immunoglobulins, including a 74% drop in IgA and pathogenic Gd-IgA1, consistent with APRIL pathway inhibition.
Zigakibart was well tolerated throughout. Most adverse events were mild or moderate, with no treatment-related serious infections or discontinuations. Infections were the most common AEs; the study's conduct coincided with a high prevalence of COVID-19 in the participating countries.
This is the longest duration of eGFR stabilisation reported for an anti-APRIL agent in IgAN. “These long-term results build confidence in zigakibart as a potential cornerstone therapy for IgAN,” said Prof. Barratt. “We’re excited to see how the upcoming Phase 3 trials will further define its role.”
The global Phase 3 BEYOND study is now evaluating zigakibart in a broader population, with primary proteinuria endpoints at 40 weeks and long-term kidney function through 104 weeks. An open-label extension (BEYONDx) trial is also underway.5
ENDS
Notes to editors:
A reference to the ERA Congress must be included in all coverage and/or articles associated with this study. For more information or to arrange an expert interview, please contact press@era-online.org
About the lead study authors:
Professor Jonathan Barratt is the Mayer Professor of Renal Medicine at the University of Leicester, UK. A leading authority in glomerular diseases, Prof. Barratt’s research focuses on the pathogenesis and treatment of IgA nephropathy. He has authored numerous peer-reviewed articles and leads several international clinical trials aimed at developing disease-modifying therapies for kidney conditions.
About the European Renal Association (ERA):
With more than 28,000 active members, the ERA is one of the biggest nephrology associations worldwide leading European nephrology, and one of the most important European medical associations. It organises annual congresses and several educational and scientific activities. The ERA also collects data and performs epidemiological studies through its Registry. The Society supports fellowships and educational/research projects through its committees and working groups. Its publications are NDT, CKJ (Open Access journal), and the ERA Neph-Manual, an e-book hosted on the ERA e-learning platform.
Website: www.era-online.org
The 62nd ERA Congress takes place between June 4-7, both virtually and live in Vienna, Austria.
References:
- Barratt J., Lee E.Y., Kim S.G., et al. (2025). Sustained Long-Term Efficacy and Safety of Zigakibart Over 100 Weeks in Patients with IgA Nephropathy. Presented at ERA Congress; 5 June 2025; Vienna, Austria.
- Caster, D.J., King, L.S., Rovin, B.H., et al. (2024). The treatment of primary IgA nephropathy: Change, change, change. American Journal of Kidney Diseases, 83(2), 229–240.
- Pitcher, D., Braddon, F., Hendry, B., Mercer, A., Osmaston, K., Saleem, M. A., Steenkamp, R., Wong, K., Turner, A. N., Wang, K., Gale, D. P., & Barratt, J. (2023). Long-Term Outcomes in IgA Nephropathy. Clinical journal of the American Society of Nephrology : CJASN, 18(6), 727–738. https://doi.org/10.2215/CJN.0000000000000135
- Myette J.R., Kano, T., Suzuki, H. et al. (2019). A Proliferation-Inducing Ligand (APRIL) targeted antibody is a safe and effective treatment of murine IgA nephropathy. Kidney International. 96(1):104-116.
- Mathur M., Barratt J., Chacko, B., et al. (2024). A Phase 2 Trial of Sibeprenlimab in Patients with IgA Nephropathy. New England Journal of Medicine. 390:20-31.