The emergence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) variants with potential resistance to existing drugs emphasizes the need for new therapeutic modalities with broad variant activity. Here we show that ensovibep, a trispecific DARPin (designed ankyrin repeat protein) clinical candidate, can engage the three units of the spike protein trimer of SARS-CoV-2 and inhibit ACE2 binding with high potency, as revealed by cryo-electron microscopy analysis. The cooperative binding together with the complementarity of the three DARPin modules enable ensovibep to inhibit frequent SARS-CoV-2 variants, including Omicron sublineages BA.1 and BA.2. In Roborovski dwarf hamsters infected with SARS-CoV-2, ensovibep reduced fatality similarly to a standard-of-care monoclonal antibody (mAb) cocktail. When used as a single agent in viral passaging experiments in vitro, ensovibep reduced the emergence of escape mutations in a similar fashion to the same mAb cocktail. These results support further clinical evaluation of ensovibep as a broad variant alternative to existing targeted therapies for Coronavirus Disease 2019 (COVID-19).

对现有药物具有潜在耐药性的严重急性呼吸综合征冠状病毒 2 (SARS-CoV-2) 变体的出现强调了对具有广泛变体活性的新治疗方式的需求。在这里，我们表明，冷冻电子显微镜分析显示，ensovibep 是一种三特异性 DARPin（设计的锚蛋白重复蛋白）临床候选药物，可以与 SARS-CoV-2 刺突蛋白三聚体的三个单元结合，并高效抑制 ACE2 结合。三个 DARPin 模块的协同结合和互补性使 ensovibep 能够抑制常见的 SARS-CoV-2 变体，包括 Omicron 亚系 BA.1 和 BA.2。在感染 SARS-CoV-2 的 Roborovski 侏儒仓鼠中，ensovibep 降低了死亡率，与标准护理单克隆抗体 (mAb) 混合物类似。当在体外病毒传代实验中用作单一药物时，ensovibep 以与相同 mAb 混合物类似的方式减少逃逸突变的出现。这些结果支持对 ensovibep 作为 2019 年冠状病毒病 (COVID-19) 现有靶向疗法的广泛变体替代方案进行进一步的临床评估。