StA-IFN-1 is an inhibitor of the interferon (IFN) induction pathway with an IC50 value of 4.1 μM in a GFP reporter assay for IFN induction similar to TPCA-1 , which specifically inhibits the IKKβ component of the IFN induction pathway. It does not show inhibitory activity in a GFP reporter assay for IFN signaling in which ruxolitinib , which is specific for the IFN signaling component JAK1, is active. StA-IFN-1 reduces the levels of IFN-β, but not ISG MxA, mRNA, suggesting that it is selective for the IFN induction pathway and not the IFN signaling pathway.
STA-1474 is a water soluble prodrug of ganetespib (formerly STA-9090). STA-1474 will metabolized to Ganetespib, which is a potent HSP90 inhibitor previously shown to kill canine tumor cell lines in vitro and inhibit tumor growth in the setting of murine xenografts. The purpose of the following study was to extend these observations and investigate the safety and efficacy of STA-1474 in dogs with spontaneous tumors.