From a genome-wide screen of RNAi molecules against SARS-CoV-2 to a validated broad-spectrum and potent prophylaxis

Expanding the arsenal of prophylactic approaches against SARS-CoV-2 is of utmost importance, specifically those strategies that are resistant to antigenic drift in Spike. Here, we conducted a screen of over 16,000 RNAi triggers against the SARS-CoV-2 genome, using a massively parallel assay to identify hyper-potent siRNAs. We selected Ten candidates for in vitro validation and found five siRNAs that exhibited hyper-potent activity (IC50 < 20 pM) and strong blockade of infectivity in live-virus experiments. We further enhanced this activity by combinatorial pairing of the siRNA candidates and identified cocktails that were active against multiple types of variants of concern (VOC). We then examined over 2,000 possible mutations in the siRNA target sites by using saturation mutagenesis and confirmed broad protection of the leading cocktail against future variants. Finally, we demonstrated that intranasal administration of this siRNA cocktail effectively attenuates clinical signs and viral measures of disease in the gold-standard Syrian hamster model. Our results pave the way for the development of an additional layer of antiviral prophylaxis that is orthogonal to vaccines and monoclonal antibodies. A genome-wide screen of 16,471 RNAi triggers targeting SARS-CoV-2 genome by Sens.AI. identifies hyper-potent RNAi candidates against SARS-CoV-2 that are further validated in vitro and in vivo.

Automated summary

A genome-wide screen identified hyper-potent RNAi candidates against SARS-CoV-2, which were further validated in vitro and in vivo. These siRNAs exhibited strong activity against multiple variants of concern and provided broad protection. Intranasal administration of the siRNA cocktail effectively attenuated clinical signs and viral measures in a hamster model, highlighting the potential for an additional layer of antiviral prophylaxis.