IACS-8779 is a potent STING agonist that efficiently stimulates interferon gene activity and exhibits strong systemic antitumor effects.

Mice bilaterally implanted with B16-Ova tumors received intra-tumoral injections of IACS-8779 (compound 1a) at a 10 μg dose solely on one flank at intervals of three days, specifically on days 6, 9, and 12 post-implantation. While IACS-8779 demonstrated comparable antitumor efficacy on the treated flank, it elicited superior tumor regression on the untreated, contralateral flank. This indicates a stronger systemic immune response by IACS-8779 than that achieved by benchmark analogs. Furthermore, treatment with IACS-8779 resulted in a higher rate of mice being cured of tumors on both flanks, surpassing the outcomes observed with benchmark treatments.