Phio Pharmaceuticals Corp., a biotechnology company, develops immuno-oncology therapeutics in the United States. It offers INTASYL therapeutic platform focuses on silencing tumor-induced suppression of the immune system. The company develops PH-762, which targets the checkpoint protein PD-1 that prevent T cells from attacking various cells for used in adoptive cell transfer (ACT); PH-804 that targets the suppressive immune receptor TIGIT, which is a checkpoint protein present on T cells and natural killer cells for used in ACT; and PH-790 which targets PD-L1 protein that prevent cancer cells from inactivating T cells and attack the cancer. It has collaboration with AgonOx, Inc. on clinical development of novel immunotherapy drugs targeting key regulators of the immune response to cancer. The company was formerly known as RXi Pharmaceuticals Corporation and changed its name to Phio Pharmaceuticals Corp. in November 2018. Phio Pharmaceuticals Corp. was incorporated in 2011 and is headquartered in Marlborough, Massachusetts.