Phio Pharmaceuticals Corp. develops immuno-oncology therapeutics in the United States. It offers INTASYL therapeutic platform focuses on targeting tumor and immune cells by regulating genes of the immune system. The company develops PH-762 that activates immune cells to recognize and kill cancer cells by reducing the expression of the checkpoint protein PD-1 for immunotherapy in adoptive cell transfer (ACT); PH-894 that silences the epigenetic protein BRD4, which is an intracellular regulator of gene expression for use in ACT; and PH-804 that targets the suppressive immune receptor TIGIT, which is a checkpoint protein present on T cells and natural killer cells for use in ACT. It has collaborations with AgonOx Inc. on clinical development of novel T cell-based cancer immunotherapies. 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.