Laninamivir (R-125489) prodrug with improved in vivo efficacy than R-125489 and Zanamivir in a mouse influenza virus A (IAV) infection model.
Laninamivir octanoate (CS-8958) is the prodrug form of Laninamivir (R-125489), a potent inhibitor agianst the neuraminidase (NA) activities of various type A and B influenza viruses, including subtypes N1 to N9 and Oseltamivir-resistant strains. When administered intranasally (3X 0.2 μmol/kg; 4 h before, 4 h & 18 h post infection), CS-8958 shows improved in vivo efficacy (100% survival rate on day 20 post infecfion) than R-125489 (100/30/20% survival rate on day 7/10/20 post infecfion) and Zanamivir (100%/0% death on day 7/10) in a mouse influenza virus A/Puerto Rico/8/34 infection model, with prolonged survival effect post a single dosage given even 7 days before infection. Note: Laninamivir octanoate is mainly used for in vivo studies, it exhibits only weak to little antiviral potency before it is converted to the active drug form.