BACKGROUND As Omicron is prompted to replicate in the upper airway, neutralizing antibodies (NAbs) delivered through inhalation might inhibit early-stage infection in the respiratory tract. Thus, elucidating the prophylactic efficacy of NAbs via nasal spray addresses an important clinical need.METHODS The applicable potential of a nasal spray cocktail containing 2 NAbs was characterized by testing its neutralizing potency, synergetic neutralizing mechanism, emergency protective and therapeutic efficacy in a hamster model, and pharmacokinetics/pharmacodynamic (PK/PD) in human nasal cavity.RESULTS The 2 NAbs displayed broad neutralizing efficacy against Omicron, and they could structurally compensate each other in blocking the Spike-ACE2 interaction. When administrated through the intranasal mucosal route, this cocktail demonstrated profound efficacy in the emergency prevention in hamsters challenged with authentic Omicron BA.1. The investigator-initiated trial in healthy volunteers confirmed the safety and the PK/PD of the NAb cocktail delivered via nasal spray. Nasal samples from the participants receiving 4 administrations over a course of 16 hours demonstrated potent neutralization against Omicron BA.5 in an ex vivo pseudovirus neutralization assay.CONCLUSION These results demonstrate that the NAb cocktail nasal spray provides a good basis for clinical prophylactic efficacy against Omicron infections.TRIAL REGISTRATION www.chictr.org.cn, ChiCTR2200066525.FUNDING The National Science and Technology Major Project (2017ZX10202203), the National Key Research and Development Program of China (2018YFA0507100), Guangzhou National Laboratory (SRPG22-015), Lingang Laboratory (LG202101-01-07), Science and Technology Commission of Shanghai Municipality (YDZX20213100001556), and the Emergency Project from the Science & Technology Commission of Chongqing (cstc2021jscx-fyzxX0001).
Xinghai Zhang, Feiyang Luo, Huajun Zhang, Hangtian Guo, Junhui Zhou, Tingting Li, Shaohong Chen, Shuyi Song, Meiying Shen, Yan Wu, Yan Gao, Xiaojian Han, Yingming Wang, Chao Hu, Xiaodong Zhao, Huilin Guo, Dazhi Zhang, Yuchi Lu, Wei Wang, Kai Wang, Ni Tang, Tengchuan Jin, Menglu Ding, Shuhui Luo, Cuicui Lin, Tingting Lu, Bingxia Lu, Yang Tian, Chengyong Yang, Guofeng Cheng, Haitao Yang, Aishun Jin, Xiaoyun Ji, Rui Gong, Sandra Chiu, Ailong Huang