Biological Activity
Tecovirimat(ST-246) is an orally bioavailable antipoxvirus compound; potent and selective active against multiple orthopoxviruses with EC50 about 10 nM.
In Vitro
ST-246 targets the cowpox virus V061 gene, which encodes a major envelope protein homologous to the vaccinia virus F13L gene product. The antiviral potency and selectivity of ST-246 was measured in CPE assays against a panel of DNA- and RNA-containing viruses. In these assays, the EC50 for inhibition of vaccinia virus was determined to be 0.01 μM, while the EC50 values for inhibition of unrelated viruses were >40 μM [1]. ST-246 was evaluated for activity against cowpox virus (CV), vaccinia virus (VV), and ectromelia virus (ECTV) and had an in vitro 50% effective concentration (EC50) of 0.48 microM against CV, 0.05 microM against VV, and 0.07 microM against ECTV. The selectivity indices were >208 and >2,000 for CV and VV, respectively. The in vitro antiviral activity of ST-246 was significantly greater than that of cidofovir, which had an EC50 of 41.1 microM against CV and 29.2 microM against VV, with selectivity indices of >7 and >10, respectively [2].
In Vivo
Mice were treated with placebo (vehicle), ST-246 administered by oral gavage at 50 mg/kg twice a day (b.i.d.) for 14 days, or CDV administered as a single intraperitoneal (i.p.) injection at 100 mg/kg. ST-246-treated mice mounted a protective immune response to vaccinia virus infection [1]. ST-246 administered once daily by oral gavage to mice infected intranasally with CV beginning 4 h or delayed until 72 h postinoculation was highly effective when given for a 14-day duration using 100, 30, or 10 mg/kg of body weight. When 100 mg/kg of ST-246 was administered to VV-infected mice, a duration of 5 days was sufficient to significantly reduce mortality even when treatment was delayed 24 h postinoculation. Viral replication in liver, spleen, and kidney, but not lung, of CV- or VV-infected mice was reduced by ST-246 compared to levels for vehicle-treated mice [2].
References & source
1: Russo AT, Berhanu A, Bigger CB, Prigge J, Silvera PM, Grosenbach DW, Hruby D. Co-administration of tecovirimat and ACAM2000™ in non-human primates: Effect of tecovirimat treatment on ACAM2000 immunogenicity and efficacy versus lethal monkeypox virus ch
Published experimental findings depend on the model and assay conditions. They do not guarantee equivalent performance in every application. For laboratory research use only.
