Pegcetacoplan is a treatment option for adolescents with C3G or IC-MPGN

The C3/C3b inhibitor pegcetacoplan showed efficacy in reducing proteinuria and stabilising eGFR compared with placebo in the subgroup of adolescents with C3 glomerulopathy or primary (idiopathic) immune complex membranoproliferative glomerulonephritis (IC-MPGN) in the VALIANT trial, consistent with the overall results.

Dr Antonio Mastrangelo (Policlinico of Milan, Italy) presented a post-hoc analysis of the double-blind, randomised, phase 3 VALIANT trial (NCT05067127), assessing 26 weeks of pegcetacoplan versus placebo in adolescents (12–17 years) or adults (≥18 years) with primary C3 glomerulopathy or IC-MPGN with/without prior renal transplant [1]. In adolescents, subcutaneous weight-based pegcetacoplan (up to 1,080 mg) was administered in a twice-weekly regimen.

Of the 124 participants included in the trial, 44% (n=55) were adolescents. Proteinuria improved starting week 4 and reached a least-squares mean reduction of 73.6% with pegcetacoplan versus a 3.7% increase with placebo at week 26, corresponding to a 74.5% (95% CI 58.5–84.3) relative reduction versus placebo (nominal P<0.0001). These results were similar to those seen in the overall population. Furthermore, pegcetacoplan versus placebo led to eGFR stabilisation, with a change from baseline to week 26 of +0.7 vs -9.0 mL/min/1.73 m² (nominal P=0.0506). The safety profile in adolescents was similar to that seen in adults, with no discontinuations due to adverse events, no graft loss or rejection, and only 1 serious adverse event (pyrexia) reported.

“In this subcohort, pegcetacoplan allowed adolescents to achieve an impressive urinary protein reduction versus placebo as well as eGFR stabilisation,” said Dr Mastrangelo. “The data on histopathology is not available in the adolescent cohort, but it is worth noting that 70% of adult patients achieved zero glomerular C3 staining at renal biopsy. Furthermore, pegcetacoplan was well-tolerated, consistent with the previous trials, and 2,000 total patients now had pegcetacoplan exposure.”

1. Vivarelli M et al. Targeted treatment with pegcetacoplan for adolescents with C3G or primary (idiopathic) IC-MPGN in the VALIANT phase 3 trial. 62nd ERA Congress, 4–7 June 2025, Vienna, Austria.

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Posted on 22 August 202525 August 2025