A potent neutralizing antibody provides protection against SARS-CoV-2 Omicron and Delta variants via nasal delivery

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is still rapidly spreading worldwide. Many drugs and vaccines have been approved for clinical use show efficacy in the treatment and prevention of SARS-CoV-2 infections. However, the emergence of SARS-CoV-2 variants of concern (VOCs), such as Delta (B.1.617.2) and the recently emerged Omicron (B.1.1.529), has seriously challenged the application of current therapeutics. Therefore, there is still a pressing need for identification of new broad-spectrum antivirals. Here, we further characterized a human antibody (586G), which we previously isolated from a patient, with robust authentic virus-neutralizing activity that inhibits the Delta and Omicron variants with half-maximal inhibitory concentrations (IC50) of 1.69 ng/ml and 54.31 ng/ml, respectively. 586G shows prophylactic and therapeutic efficacy in hamsters challenged with the Delta and Omicron variants through nasal delivery. Notably, a very low dosage (2 mg/kg daily) of 586G efficiently prevented virus variant replication in the lungs. These advantages may overcome the efficacy limitation of currently approved neutralizing antibodies that can be administered only by intravenous injection. In general, 586G is a promising prophylactic and therapeutic candidate against current circulating VOCs and even future emerging mutants. To the best of our knowledge, 586G is one of the most potent neutralizing antibodies against Omicron, with a broader spectrum than those approved for clinical use. 586G could be developed as a nebulized therapy, which would be more cost effective and user friendly and enhance the clinical outcome compared to that obtained with direct nasal delivery.

Xinghai Zhang, Huajun Zhang, Tingting Li, Shaohong Chen, Feiyang Luo, Junhui Zhou, Peiyi Zheng, Shuyi Song, Yan Wu, Tengchuan Jin, Ni Tang, Chengyong Yang, Guofeng Cheng, Ruil Gong, Sandra Chiu, Ailong Huang