Potent and long-acting dimeric inhibitors of influenza virus neuraminidase are effective at a once-weekly dosing regimen.

Dimeric derivatives (compounds 7 to 9) of the influenza virus neuraminidase inhibitor zanamivir (compound 2), which have linking groups of 14 to 18 atoms in length, are approximately 100-fold more potent inhibitors of influenza virus replication in vitro and in vivo than zanamivir. The observed optimum linker length of 18 to 22 A, together with observations that the dimers cause aggregation of isolated neuraminidase tetramers and whole virus, indicate that the dimers benefit from multivalent binding via intertetramer and intervirion linkages. The outstanding long-lasting protective activities shown by compounds 8 and 9 in mouse influenza infectivity experiments and the extremely long residence times observed in the lungs of rats suggest that a single low dose of a dimer would provide effective treatment and prophylaxis for influenza virus infections.

An orally bioavailable oxime ether capsid binder with potent activity against human rhinovirus.

A series of capsid-binding compounds was screened against human rhinovirus (HRV) using a CPE based assay. The ethyl oxime ether 14 was found to have outstanding anti-HRV activity (median IC(50) 4.75 ng/mL), and unlike the equivalent ethyl ester compound 3 (Pirodavir), it has good oral bioavailability, making it a promising development candidate. Compound 14 illustrates that an oxime ether group can act as a metabolically stable bioisostere for an ester functionality.