Pimodivir (VX-787), an influenza A virus polymerases inhibitor via oral, interacts with the viral PB2 subunit.

Pimodivir is very potent against influenza A strains,and shows potent activity against all influenza A virus strains tested, with an EC50 range of 0.13 to 3.2 nM.

In mouse influenza model,Pimodivir (1, 3, or 10 mg/kg, bid) provided complete survival. Pimodivir (2, 6, and 20 mg/kg/day, p.o.) completely prevent death in the H1N1pdm virus infection in mice.

Virus sensitivity to neuraminidase inhibitors is determined by the chemiluminescent neuraminidase inhibitor assay using an NA-XTD kit. Viruses are diluted in NA-XTD assay buffer (26 mM morpholineethanesulfonic acid, 4 mM CaCl2 [pH 6.0]) such that the signal-to-noise ratio is greater than 40:1. Resistance is defined as determination of a 50% inhibitory concentration greater than 10-fold the mean for the type/subtype

Pimodivir is dissolved in DMSO.The compound cytotoxicity and efficacy testing is performed in 96-well plates with macrophages at 95% confluence. The compounds are added to the medium, and 30 min later, the cells are infected with virus or non-infected. The cell viability is analyzed with the Cell Titer Glo assay at 24 hpi. The luminescence is read with a PHERAstar FS plate reader.

The mice, infected intranasally with influenza virus, are given Pimodivir(prepared in 0.5% methylcellulose) twice a day.