title: Characterization of an influenza A (H3N2) virus resistant to the cyclopentane neuraminidase inhibitor RWJ-270201.
abstract: The novel influenza virus neuraminidase (NA) inhibitor, (1S,2S,3R,4R)-3-[(1S)-(acetylamino)-2-ethylbutyl]-4-[(aminoiminomethyl)amino]-2-hydroxy-cyclopentanecarboxylic acid (RWJ-270201, BCX-1812), is a potent inhibitor of influenza A and B viruses in cell culture and in infected mice. A mouse-adapted strain of influenza A/Shangdong/09/93 (H3N2) virus was serially passaged in the presence of 1 microM compound. After the fourth passage, breakthrough of resistant virus occurred. By the tenth passage, a twice plaque purified isolate was obtained which could replicate in 10 microM inhibitor. The 50% effective concentration (EC(50)) values for RWJ-270201 against wild-type and resistant viruses, determined by using a cytopathic effect inhibition assay, were 0.007 and 23 microM, respectively. Cross-resistance to zanamivir and oseltamivir carboxylate was observed. The hemagglutinin (HA) and NA genes of the virus were sequenced to determine the mutation(s) which conferred drug resistance. No differences were found between the resistant and wild-type viruses in the NA gene. However, a point mutation resulting in a single amino acid change (Lys189Glu) was found in the resistant viral HA. The wild-type and resistant viruses were compared for virulence in BALB/c mice. The resistant virus was approximately tenfold less virulent than the wild-type virus based upon virus challenge dose. Mice infected with a lethal dose of the resistant virus could still be effectively treated with RWJ-270201. Thus, the HA mutation may allow for the spread of the virus in cell culture in the presence of the NA inhibitor, but not in mice.
authors.affiliation: Department of Animal, Dairy and Veterinary Sciences, Institute for Antiviral Research, Utah State University, Logan, UT 84322-5600, USA. dsmee@cc.usu.edu
authors.forename: D F
authors.initials: DF
authors.lastname: Smee
authors.forename: R W
authors.initials: RW
authors.lastname: Sidwell
authors.forename: A C
authors.initials: AC
authors.lastname: Morrison
authors.forename: K W
authors.initials: KW
authors.lastname: Bailey
authors.forename: E Z
authors.initials: EZ
authors.lastname: Baum
authors.forename: L
authors.initials: L
authors.lastname: Ly
authors.forename: P C
authors.initials: PC
authors.lastname: Wagaman
mesh_terms: D000146:Acids, Carbocyclic; D000818:Animals; D000998:Antiviral Agents / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D002460:Cell Line; D002461:Cell Line, Transformed; D003517:Cyclopentanes / Q000737:chemistry / Q000494:pharmacology* / Q000627:therapeutic use; D004285:Dogs; D024882:Drug Resistance, Viral; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use; D006146:Guanidines; D006801:Humans; D053122:Influenza A Virus, H3N2 Subtype; D009980:Influenza A virus / Q000187:drug effects / Q000201:enzymology* / Q000235:genetics* / Q000472:pathogenicity; D007251:Influenza, Human / Q000188:drug therapy / Q000821:virology; D051379:Mice; D008807:Mice, Inbred BALB C; D009154:Mutation / Q000235:genetics; D009439:Neuraminidase / Q000037:antagonists & inhibitors*; D014774:Virulence / Q000235:genetics
chemical_list: D000146:Acids, Carbocyclic; D000998:Antiviral Agents; D003517:Cyclopentanes; D004791:Enzyme Inhibitors; D006146:Guanidines; D009439:Neuraminidase; C414210:peramivir