Mechanism-Based Covalent Neuraminidase Inhibitors with Broad-Spectrum Influenza Antiviral Activity

Adding to the Antiviral Arsenal The envelope of influenza virus contains two immunodominant glycoproteins: hemagglutinin and neuraminidase (NA). Existing antivirals like zanamivir (Relenza) and oseltamivir (Tamiflu) target NA; however, the development of drug resistance is a problem. Kim et al. (p. 71 , published online 21 February) now report a different class of NA inhibitors. NA catalyzes the removal of sialic acids from the surface of host cells to initiate entry. Discovery of a NA–sialic acid intermediate led to the production of sialic acid analogs that bound covalently to NA and inhibited its enzymatic activity. These compounds showed activity against a wide variety of influenza strains, inhibited viral replication in cell culture, and were able to protect mice against influenza infection. Protection of mice was equivalent to protection seen from zanamivir. Moreover, the compounds showed activity against drug-resistant strains in vitro. These compounds represent a potentially useful addition to the arsenal of antivirals used to treat influenza infection.