ERA Congress: Long-term data show sustained efficacy and safety of zigakibart in patients with IgA nephropathy

VIENNA, June 5, 2025 /PRNewswire/ -- 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 62^nd ERA Congress demonstrate sustained proteinuria remission, stable kidney function, and a reassuring safety profile.

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. Many patients are unaware they have the condition until significant kidney damage has occurred, and 50% of IgAN patients will ultimately develop kidney failure.

By targeting the APRIL pathway and reducing production of pathogenic galactose-debecause ofgA1), zigakibart addresses a key driver of disease progression. "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.

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 particularly encouraging," 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 coincided with a high prevalence of COVID-19.

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.