Jennerex Biotherapeutics, Inc. (now owned by SillaJen) was an American private biopharmaceutical company that developed the oncolytic viruses JX-594 and JX-929 among others. By creating oncolytic viruses that can (1) kill tumor cells directly through lysis, (2) activate the immune system by delivering genes that encode immunostimulants and by overcoming tumor cell-induced immunological tolerance, and (3) reduce tumor nutrient supply through the destruction of blood vessels, Jennerex aimed to create a novel approach to treating and possibly curing cancer.