Summary: Stapokibart (CM310) is a humanized IL-4Rα monoclonal antibody currently undergoing phase 3 trials for type 2 inflammatory diseases. In contrast to dupilumab, which bound exclusively to human IL-4Rα, stapokibart demonstrated cross-species reactivity to IL-4Rα from human, cynomolgus monkey, and rat. Stapokibart exhibited comparable blocking activity to dupilumab. Epitope mapping revealed that stapokibart bound to distinct sites on IL-4Rα compared to dupilumab. In vitro assays showed that stapokibart was comparable or numerically superior in blocking IL-4Rα-mediated signaling compared to dupilumab. In vivo studies further demonstrated that stapokibart effectively inhibited the progression of type 2 inflammation. Pharmacokinetic studies revealed a circulating half-life of approximately 298–351 h in cynomolgus monkeys and 55–142 h in rats for stapokibart. Toxicity studies indicated a favorable safety profile in cynomolgus monkeys and rats. The preclinical evaluation of stapokibart supports its clinical development.
