Definition

An oncolytic herpes simplex virus type 1 (HSV-1) genetically engineered to express the human immunostimulating cytokines interleukin (IL)-2 and IL-12, with potential immunostimulatory and antineoplastic activities. Upon intratumoral administration, oncolytic HSV-1 expressing IL-2 and IL-12 KB707 infects and replicates in tumor cells causing viral-mediated tumor cell lysis. The released virus particles, in turn, infect and replicate in neighboring tumor cells. Tumor antigens released from the lysed tumor cells also activate the immune system to induce a tumor-specific systemic immune and cytotoxic T-lymphocyte (CTL) response, thereby killing nearby non-infected tumor cells. In addition, oncolytic HSV-1 expressing IL-2 and IL-12 KB707 promotes the secretion of IL-2 and IL-12 by the tumor cells locally in the tumor microenvironment (TME). This may further stimulate anti-tumor immune responses, increase tumor cell killing and decrease tumor cell proliferation.