filibuvir filibuvir filibuvir (also known as pf-00868554, pf-868554) was a non-nucleoside orally available ns5b inhibitor developed by pfizer for the treatment of hepatitis c. it binds to the non-catalytic thumb ii allosteric pocket of ns5b viral polymerase and causes a decrease in viral rna synthesis. it is a potent and selective inhibitor, with a mean ic50 of 0.019 μm against genotype 1 polymerases. several filibuvir-resistant mutations have been identified, m423 being the most common that occurred after filibuvir monotherapy. it was intended to be taken twice-daily. filibuvirclinical dataother namespf-00868554routes ofadministrationoralatc codenonelegal statuslegal status development terminated identifiers iupac name (2r)-2-cyclopentyl-2--5-triazolopyrimidin-2-yl)methyl]-4-hydroxy-3h-pyran-6-one cas number877130-28-4pubchem cid54708673chemspider26286922unii198j479y2lkeggd09616chemblchembl490672pdb ligandag0 (pdbe, rcsb pdb)comptox dashboard (epa)dtxsid601007768 chemical and physical dataformulac29h37n5o3molar mass503.647 g·mol−13d model (jsmol)interactive image smiles ccc1=cc(=cc(=n1)cc)cc2(cc(=c(c(=o)o2)cc3=nn4c(=cc(=nc4=n3)c)c)o)c5cccc5 inchi inchi=1s/c29h37n5o3/c1-5-22-14-20(15-23(6-2)31-22)11-12-29(21-9-7-8-10-21)17-25(35)24(27(36)37-29)16-26-32-28-30-18(3)13-19(4)34(28)33-26/h13-15,21,35h,5-12,16-17h2,1-4h3/t29-/m1/s1key:slvapeztbdbapi-gdlzymkvsa-n its investigation was discontinued in february 2013 due to strategic reasons.