Definition

An off-the-shelf (OTS) cancer vaccine containing a live-attenuated strain of the Gram-positive bacterium Listeria monocytogenes (Lm) encoding a fusion protein composed of specific prostate cancer (PC) neoantigens fused to a fragment of the immunostimulant listeriolysin O (LLO) protein, with potential immunostimulatory and antineoplastic activities. Upon administration of the Lm-LLO-PC neoantigens vaccine ADXS-504, the expressed LLO-PC neoantigens is processed by antigen presenting cells (APCs), presented to the immune system by both major histocompatibility complex (MHC) I and II molecules, and activates the immune system to exert both an innate and adaptive immune response involving the recruitment and activation of T lymphocytes against neoantigen-expressing prostate cancer cells as well as the inhibition of tumor-infiltrating T regulatory cells (T regs) and myeloid-derived suppressor cells (MDSCs). This further modulates the tumor microenvironment (TME) and further results in tumor cell eradication. The neoantigens in ADXS-504 are composed of public hotspot mutations and proprietary tumor associated antigen (TAAs).