#2-79E. Targeting C3: Pegcetacoplan Efficacy in C3 Glomerulopathy and IC-MPGN (NEJM, 2025)

How do we effectively halt the progression of rare, complement-mediated kidney diseases like C3 Glomerulopathy (C3G) and primary Immune-Complex MPGN (IC-MPGN)? These severe glomerulopathies often result in abnormal glomerular C3 deposition, leading to irreversible kidney damage, with up to 50% of patients progressing to advanced kidney failure within 10 years. This Phase 3, double-blind, placebo-controlled VALIANT trial assessed the efficacy and safety of pegcetacoplan, a targeted inhibitor of C3 and C3b, in adolescents and adults with C3G or IC-MPGN. The primary analysis demonstrated that pegcetacoplan achieved a significant 68.1% relative reduction in the urinary protein-to-creatinine ratio compared to placebo at week 26. This strong response suggests a promising therapeutic approach that addresses the central pathogenic driver. However, clinicians should note that while C3 staining decreased markedly in treated patients, the change in the C3G histologic activity score did not reach statistical significance between groups. This research is crucial as it offers nephrologists and transplant specialists a novel, targeted therapeutic option for conditions currently lacking effective treatments, potentially stabilizing eGFR and improving long-term kidney prognosis for these high-risk patients.

Citation: Fakhouri, F., et al. Trial of Pegcetacoplan in C3 Glomerulopathy and Immune-Complex MPGN. N Engl J Med. 2025. DOI: 10.1056/NEJMoa2501510

Disclaimer: This audio summary is based on personal interpretation and does not guarantee the exact content of the original paper. Please refer to the original article for details.