Established in 2011 and headquartered in Marlborough, Massachusetts, Phio Pharmaceuticals Corp. is a biotechnology firm dedicated to advancing immuno-oncology treatments within the United States. Central to its approach is the proprietary INTASYL therapeutic platform, engineered to counteract the mechanisms by which tumors evade or suppress the body's natural immune response. Its pipeline features several promising candidates: PH-762 is designed to inhibit the PD-1 checkpoint protein found on immune cells, with development focused on applications in adoptive cell transfer (ACT). PH-804 targets TIGIT, another suppressive immune receptor and checkpoint protein present on both T cells and natural killer cells, also intended for ACT. PH-790 focuses on modulating the PD-L1 protein, which typically prevents immune cells from attacking healthy tissues. Phio Pharmaceuticals actively collaborates with leading institutions such as Gustave Roussy, Medigene AG, and Helmholtz Zentrum München. Furthermore, it maintains a strategic partnership with AgonOx Inc. specifically for the clinical advancement of innovative T cell-based immunotherapies for cancer. The company underwent a name change in November 2018, transitioning from its former identity as RXi Pharmaceuticals Corporation.