title: Novel pandemic influenza A(H1N1) viruses are potently inhibited by DAS181, a sialidase fusion protein.
abstract: BACKGROUND
  The recent emergence of a novel pandemic influenza A(H1N1) strain in humans exemplifies the rapid and unpredictable nature of influenza virus evolution and the need for effective therapeutics and vaccines to control such outbreaks. However, resistance to antivirals can be a formidable problem as evidenced by the currently widespread oseltamivir- and adamantane-resistant seasonal influenza A viruses (IFV). Additional antiviral approaches with novel mechanisms of action are needed to combat novel and resistant influenza strains. DAS181 (Fludase) is a sialidase fusion protein in early clinical development with in vitro and in vivo preclinical activity against a variety of seasonal influenza strains and highly pathogenic avian influenza strains (A/H5N1). Here, we use in vitro, ex vivo, and in vivo models to evaluate the activity of DAS181 against several pandemic influenza A(H1N1) viruses.
  
  
  RESULTS
  The activity of DAS181 against several pandemic influenza A(H1N1) virus isolates was examined in MDCK cells, differentiated primary human respiratory tract culture, ex-vivo human bronchi tissue and mice. DAS181 efficiently inhibited viral replication in each of these models and against all tested pandemic influenza A(H1N1) strains. DAS181 treatment also protected mice from pandemic influenza A(H1N1)-induced pathogenesis. Furthermore, DAS181 antiviral activity against pandemic influenza A(H1N1) strains was comparable to that observed against seasonal influenza virus including the H274Y oseltamivir-resistant influenza virus.
  
  
  CONCLUSIONS
  The sialidase fusion protein DAS181 exhibits potent inhibitory activity against pandemic influenza A(H1N1) viruses. As inhibition was also observed with oseltamivir-resistant IFV (H274Y), DAS181 may be active against the antigenically novel pandemic influenza A(H1N1) virus should it acquire the H274Y mutation. Based on these and previous results demonstrating DAS181 broad-spectrum anti-IFV activity, DAS181 represents a potential therapeutic agent for prevention and treatment of infections by both emerging and seasonal strains of IFV.
authors.affiliation: NexBio Inc, San Diego, CA, USA.
authors.forename: Gallen B
authors.initials: GB
authors.lastname: Triana-Baltzer
authors.forename: Larisa V
authors.initials: LV
authors.lastname: Gubareva
authors.forename: John M
authors.initials: JM
authors.lastname: Nicholls
authors.forename: Melissa B
authors.initials: MB
authors.lastname: Pearce
authors.forename: Vasiliy P
authors.initials: VP
authors.lastname: Mishin
authors.forename: Jessica A
authors.initials: JA
authors.lastname: Belser
authors.forename: Li-Mei
authors.initials: LM
authors.lastname: Chen
authors.forename: Renee W Y
authors.initials: RW
authors.lastname: Chan
authors.forename: Michael C W
authors.initials: MC
authors.lastname: Chan
authors.forename: Maria
authors.initials: M
authors.lastname: Hedlund
authors.forename: Jeffrey L
authors.initials: JL
authors.lastname: Larson
authors.forename: Ronald B
authors.initials: RB
authors.lastname: Moss
authors.forename: Jacqueline M
authors.initials: JM
authors.lastname: Katz
authors.forename: Terrence M
authors.initials: TM
authors.lastname: Tumpey
authors.forename: Fang
authors.initials: F
authors.lastname: Fang
mesh_terms: D000818:Animals; D000998:Antiviral Agents / Q000494:pharmacology*; D001980:Bronchi / Q000378:metabolism; D004285:Dogs; D005260:Female; D006801:Humans; D053118:Influenza A Virus, H1N1 Subtype / Q000378:metabolism*; D007251:Influenza, Human / Q000188:drug therapy; D007668:Kidney / Q000378:metabolism; D051379:Mice; D008807:Mice, Inbred BALB C; D008856:Microscopy, Fluorescence / Q000379:methods; D009439:Neuraminidase / Q000737:chemistry*; D053139:Oseltamivir / Q000494:pharmacology; D011993:Recombinant Fusion Proteins / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D000998:Antiviral Agents; D011993:Recombinant Fusion Proteins; D053139:Oseltamivir; C525612:oplunofusp; D009439:Neuraminidase