Description: Ulevostinag (MK-1454; MK1454) is an investigational small molecule STING agonist with potential immunomodulatory and anticancer activities. It can be administered as an intratumoral injection and is currently being evaluated in a Phase 1 clinical trial for the treatment of solid tumors and lymphomas (ClinicalTrials.gov, NCT03010176). STING is a signaling molecule that plays an important role in the body’s first line of defense against pathogens, such as bacteria and viruses (innate immune system). When activated, STING triggers the production of inflammatory proteins that can stimulate the immune system leading to the deployment of T cells, which are important in generating an effective immune mediated response to cancer cells. MK-1454 exhibited robust tumor cytokine upregulation and effective antitumor activity. Tumor shrinkage in mouse models that are intrinsically resistant to single-agent therapy was further enhanced when treating the animals with MK-1454 in combination with a fully murinized antimouse PD-1 antibody, mDX400.