Cap-dependent endonuclease-IN-26, a potent inhibitor of cap-dependent endonuclease (CEN) with an IC50 of 286 nM, exhibits significant antiviral activity against a broad spectrum of influenza A and B strains [1].

Cap-dependent endonuclease-IN-26 (compound 2v) exhibits broad antiviral spectrum. Cap-dependent endonuclease-IN-26 shows antiviral activity against the H1N1 type, including the reverse genetic strain (rgA/WSN/33), oseltamivir-resistant strain (rgA/WSN/33-NA/H274Y), clinically isolated strain (A/PR/8/34), H3N2 A/Victoria/3/75, H3N2 A/HongKong/8/68, influenza B/Hong Kong/5/72, and influenza B/Maryland/1/59 with EC 50 values 165.1 nM, 80.4 nM, 183.0 nM, 828.8 nM, 301.5 nM, 124.3 nM, and 176.0 nM, respectively [1].

In rats, Cap-dependent endonuclease-IN-26 (compound 2v) exhibits reasonable in vivo clearance with 10.9 mL/min/kg [1]. In a mouse influenza B (B/Maryland/1/59) model, Cap-dependent endonuclease-IN-26 (compound 2v; intravenous administration; 0.08-10 mg/kg; q.d.;1 day) shows dose-dependent efficacy in an immediate treatment model [1].