Kidney Week

Abstract: TH-PO0556

Early Repeated Administration of a Novel IgG-Degrading Enzyme, Ricefidase, for Anti-GBM Disease: A Phase 2, Open-Label, Single-Arm, Multicenter Study

Session Information

• Glomerular Diseases: IgAN, IgA Vasculitis, and More
  October 22, 2026 | Location: Exhibit Hall A, Convention Center
  Abstract Time: 10:00 AM - 12:00 PM

Category: Glomerular Diseases

• 1402 Glomerular Diseases: Clinical, Outcomes, and Therapeutics

Authors

• Huang, Jing, Peking University First Hospital Department of Nephrology Renal Division, Beijing, China

Jing Huang

• Jia, Xiaoyu, Peking University First Hospital Department of Nephrology Renal Division, Beijing, China

Xiaoyu Jia, PhD

• Yan, Yan, First Affiliated Hospital of Nanchang Medical College, Department of Nephrology, Nanchang, Jiangxi, China

Yan Yan, MD

• Wang, Ying, First Affiliated Hospital of Nanchang Medical College, Department of Nephrology, Nanchang, Jiangxi, China

Ying Wang, MPH

• Zhu, Zhen, Shanghai Bao Pharmaceuticals Co., Ltd., Shanghai, China

Zhen Zhu

• Liu, Yanjun, Shanghai Bao Pharmaceuticals Co., Ltd., Shanghai, China

Yanjun Liu

• Cui, Zhao, Peking University First Hospital Department of Nephrology Renal Division, Beijing, China

Zhao Cui, MD

• Zhao, Minghui, Peking University First Hospital Department of Nephrology Renal Division, Beijing, China

Minghui Zhao, PhD

Background

Anti-glomerular basement membrane disease often progresses to kidney failure despite plasma
exchange (PLEX) and intensive immunosuppression. Ricefidase (KJ103) is a novel IgG-degrading enzyme
designed from Streptococcus equi with low pre-existing antibody. Safety and efficacy of an early
repeated administration of ricefidase was assessed in addition to standard care.

Methods

This open-label, single-arm, phase 2 trial (NCT06607016) enrolled 12 adults with anti-GBM disease at two centers in China between October 2024 and October 2025. Regimen 1 (n=8) comprised 0.25 mg/kg on Day 1 and 0.15 mg/kg on Day 8 (adjustable Day 3–10); Regimen 2 (n=4) comprised 0.25 mg/kg on Day 1 and 0.15 mg/kg on Days 4 and 7. The primary endpoint was dialysis-free at 3 and 6 months. Outcomes were compared with historical controls (2011–2020) from one participating center.

Results

Twelve patients were enrolled; baseline kidney injury was severe (median eGFR 8.1 ml/min/1.73m²), and 66.7% were dialysis-dependent. All patients survived at 6 months. 66.7% (8/12) were dialysis free at 3 months, and 75.0% (9/12) at 6 months. Among those dialysis-dependent at baseline, 62.5% (5/8) discontinued dialysis by 4 months. Kidney function improved in dialysis-free patients, with mean eGFR increasing to 33.1 ml/min/1.73 m² (Regimen 1) and 46.1 ml/min/1.73 m²(Regimen 2) at 6 months. At 6 months, dialysis dependence was lower than in historical controls (25.0% [3/12] vs 64.9% [63/97], P=0.011). Anti-GBM antibodies became negative in all patients within 6 hours (nadir at 24 hours); antibody rebound occurred in 37.5% (3/8) of Regimen 1 but in none of Regimen 2. Rescue PLEX after ricefidase was required in 25% (3/12), all in Regimen 1; no post-treatment PLEX was performed in Regimen 2. Treatment-related adverse events occurred in 8.3% (1/12), all Grade 1; no treatment-related
serious adverse events or infectious events were observed.

Conclusion

Multi-dose ricefidase plus standard immunosuppression enabled rapid and sustained clearance of anti-GBM antibodies and was associated with high 6-months dialysis-free survival.

Funding

• Commercial Support – Shanghai Bao Pharmaceuticals Co., Ltd., Shanghai, P.R. China