Engineering a Coiled-Coil Protein for DARPin Presentation as a Potent SARS-CoV-2 Therapeutic

The COVID-19 pandemic has demonstrated the need for rapid, flexible, and readily adaptable treatment options for future pandemic preparedness. Due to the speed at which viruses like SARS-CoV-2 mutate, the customary approach of using highly specific monoclonal antibodies as neutralization therapies is challenging, given their size, production complexity, and cost. Here, we leveraged rational protein design to create fusion proteins from small, antibody-mimetic proteins, Designed Ankyrin Repeat Proteins (DARPins) and a self-assembling hexameric coiled coil (CC-HEX). The fusion proteins are modular, suitable to rapidly adapt to new variants or pathogens, and enable the incorporation of both viral and serum albumin-binding functions. We demonstrated potent neutralization by HEX-DARPins against multiple variants of the SARS-CoV-2 pseudovirus. Albumin binding prolonged serum concentration and improved delivery to the lungs in mice. This work establishes HEX-DARPin fusion proteins as potential therapeutics for the treatment of COVID-19 and as a platform for the development of drugs against future viral pathogens.