PT - JOURNAL ARTICLE AU - Sylvia Rothenberger AU - Daniel L. Hurdiss AU - Marcel Walser AU - Francesca Malvezzi AU - Jennifer Mayor AU - Sarah Ryter AU - Hector Moreno AU - Nicole Liechti AU - Andreas Bosshart AU - Chloe Iss AU - Valérie Calabro AU - Andreas Cornelius AU - Tanja Hospodarsch AU - Alexandra Neculcea AU - Thamar Looser AU - Anja Schlegel AU - Simon Fontaine AU - Denis Villemagne AU - Maria Paladino AU - Yvonne Kaufmann AU - Doris Schaible AU - Iris Schlegel AU - Dieter Schiegg AU - Christof Zitt AU - Gabriel Sigrist AU - Marcel Straumann AU - Feyza Sacarcelik AU - Julia Wolter AU - Marco Comby AU - Julia M. Adler AU - Kathrin Eschke AU - Mariana Nascimento AU - Azza Abdelgawad AU - Achim D. Gruber AU - Judith Bushe AU - Olivia Kershaw AU - Heyrhyoung Lyoo AU - Chunyan Wang AU - Wentao Li AU - Ieva Drulyte AU - Wenjuan Du AU - H. Kaspar Binz AU - Rachel Herrup AU - Sabrina Lusvarghi AU - Sabari Nath Neerukonda AU - Russell Vassell AU - Wei Wang AU - Susanne Mangold AU - Christian Reichen AU - Filip Radom AU - Charles G. Knutson AU - Kamal K. Balavenkatraman AU - Krishnan Ramanathan AU - Seth Lewis AU - Randall Watson AU - Micha A. Haeuptle AU - Alexander Zürcher AU - Keith M. Dawson AU - Daniel Steiner AU - Carol D. Weiss AU - Patrick Amstutz AU - Frank J.M. van Kuppeveld AU - Michael T. Stumpp AU - Berend-Jan Bosch AU - Olivier Engler AU - Jakob Trimpert TI - Ensovibep, a novel trispecific DARPin candidate that protects against SARS-CoV-2 variants AID - 10.1101/2021.02.03.429164 DP - 2022 Jan 01 TA - bioRxiv PG - 2021.02.03.429164 4099 - http://biorxiv.org/content/early/2022/02/26/2021.02.03.429164.short 4100 - http://biorxiv.org/content/early/2022/02/26/2021.02.03.429164.full AB - SARS-CoV-2 has infected millions of people globally and continues to undergo evolution. Emerging variants can be partially resistant to vaccine induced immunity and therapeutic antibodies, emphasizing the urgent need for accessible, broad-spectrum therapeutics. Here, we report a comprehensive study of ensovibep, the first trispecific clinical DARPin candidate, that can simultaneously engage all three units of the spike protein trimer to potently inhibit ACE2 interaction, as revealed by structural analyses. The cooperative binding of the individual modules enables ensovibep to retain inhibitory potency against all frequent SARS-CoV-2 variants, including Omicron BA.1 and BA.2, as of February 2022. Moreover, viral passaging experiments show that ensovibep, when used as a single agent, can prevent development of escape mutations comparably to a cocktail of monoclonal antibodies (mAb). Finally, we demonstrate that the very high in vitro antiviral potency also translates into significant therapeutic protection and reduction of pathogenesis in Roborovski dwarf hamsters infected with either the SARS-CoV-2 wild-type or the Alpha variant. In this model, ensovibep prevents fatality and provides substantial protection equivalent to the standard of care mAb cocktail. These results support further clinical evaluation and indicate that ensovibep could be a valuable alternative to mAb cocktails and other treatments for COVID-19.Competing Interest StatementAuthors from Molecular Partners own performance share units and/or stock of the company. H.K.B. owns stock of the company. I.D. is an employee of Thermo Fisher Scientific. C.G.K.; K.K.B. and K.R. are employees of Novartis. The other authors declare no competing interests.