Solid tumors are surrounded by an immunosuppressive tumor microenvironment. Therefore, when CAR T cells try to enter the tumor, survive, and kill the cancer cells, they cannot do so effectively.
City of Hope has therefore developed with the immuno-oncology company Imugene Ltd. a therapy combining an oncolytic virus and CAR T cells that shows preclinical potential in solid tumors and allows CD19-directed CAR T cell therapies to target and eradicate solid tumors that are difficult to treat with CAR T cell therapy alone. In this research, investigators examined the ability of the genetically engineered oncolytic virus to enter tumor cells and force CD19 protein expression on the cell surface. The results of these studies showed that truncated CD19 was expressed by the tumor cells faster than the virus was able to eradicate it; thus, this gave researchers the opportunity to target this marker with CAR T cell therapy directed against CD19. In addition, the results showed that mice that were cured of their cancer with this combination exhibited prolonged protective antitumor immunity. As a result, the researchers hope to launch a phase 1 clinical trial in 2022.