From COVID-19 to the Common Cold: Novel Host-Targeted, Pan-Respiratory Antiviral Small Molecule Therapeutics

Antiviral compounds displaying remarkable features have been identified by an unconventional drug screen and advanced through animal validation. Efficacy is observed against the six viral families causing most human respiratory viral disease, irrespective of strain, including both influenza (FLUV) and SARS-CoV-2, with cell culture EC50 at or below 100 nM. Survival benefit is demonstrated in pigs against another member of family Coronaviridae, porcine epidemic diarrhea virus (PEDV), and shown equally effective in mild and severe disease. Respiratory syncytial virus (RSV) titer is reduced by drug treatment in cotton rats. A substantial barrier to viral resistance is demonstrated for FLUV. Drug resin affinity chromatography (DRAC) reveals a novel drug target: a multi-protein complex (MPC) formed transiently, in an energy-dependent fashion, and composed of host proteins implicated in both viral lifecycles and manipulation of innate immunity. The protein composition of this host MPC is modified upon viral infection, with increase or decrease of some proteins and appearance or complete loss of others. Valosin-containing protein, also known as Transitional endoplasmatic reticulum ATPase (VCP/p97), is present in the target MPC of uninfected cells and significantly increased in both FLUV and CoV infection. SQSTM1/p62, a key regulator of the autophagy pathway of innate immunity whose dysfunction is implicated in cytokine storm, is i) found in the target MPC from uninfected cells, ii) diminished in DRAC eluates by infection, and iii) restored by drug treatment of infected cells. 14-3-3 is one of likely several proteins that comprise the drug-binding site. Advanced compounds with improved pharmacokinetic (PK) properties and lung exposure are approaching criteria for a Target Product Profile. We propose these novel drug targets to comprise a previously unappreciated molecular basis for homeostasis that is modified by viruses to allow exploitation for viral propagation and is restored by treatment with the therapeutic compounds presented. This discovery has transformative implications for treatment of respiratory viral-related disease, applicable to everything from seasonal FLUV to COVID-19 and future novel respiratory viruses, due to the pan-family nature of drug activity and barrier to resistance development.