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.