A proprietary, live-attenuated, double-deleted (LADD) strain of the Gram-positive bacterium Listeria monocytogenes (Lm) encoding multiple, as of yet undisclosed, tumor-associated antigens (TAAs), with potential immunostimulatory and antineoplastic activities. Upon intravenous administration, opolimogene capmilisbac is taken up by antigen-presenting cells (APCs), including dendritic cells (DCs). The TAAs are subsequently expressed by the APCs and then processed and presented to the immune system by both major histocompatibility complex (MHC) class I and II molecules. This activates the immune system and leads to the recruitment and activation of cytotoxic T-lymphocytes (CTLs) against the TAA-expressing tumor cells, eventually resulting in tumor cell lysis. Two genes contributing to the virulence of Lm have been removed to minimize the risk of infection.