The authors appreciate the comments of Felix Poppelaars and colleagues on their article on the interpretation of adjunctive biomarkers in C3 glomerulopathy. They provide context from the APPEAR-C3G trial, which was a randomized, double-blind, multicenter, placebo-controlled, phase 3 trial. The study evaluated the efficacy and safety of iptacopan 200 mg twice daily versus placebo in adult patients with C3G for 6 months, followed by a 6-month open-label phase. All 74 randomized patients (38 on iptacopan, 36 on placebo) completed the 6-month double-blind phase, and 73 patients completed the 12-month study. Biomarker levels at baseline were comparable in both groups. Iptacopan confirmed inhibition of the alternative complement pathway by rapid onset and sustained improvement in serum C3, reduction in AP activity and terminal complement complex sC5b-9 over 12 months. These results were repeated in the placebo group after switching to the open-label phase with iptacopan.