A biomarker is a measurable characteristic that reflects the severity or presence of or is associated with some disease state and that can be used as an indicator of a particular disease state or some other physiological state of an organism. Biomarkers can be specific cells, molecules, genes, gene products, enzymes, receptors, mutated versions of any of these cellular elements or hormones that can be used to identify and/or measure the presence or progress of disease state, such as a particular cancer or tumor. Further, it is well known that tumors and cancers can express a set of tumor biomarkers that can be used to identify the presence of or measure the progress of or the effects of treatment on the tumor or cancer.
Despite the abundant use of biomarkers for diagnosing disease and monitoring progression of the same, there remains a need for developing therapeutic approaches that make use of this information to specifically target biomarkers expressed by the disease that are directly associated with the proliferation or existence of the diseased state and subsequent deterioration of a subject's overall health
Listeria monocytogenes (Lm) is an intracellular pathogen that primarily infects antigen presenting cells and has adapted for life in the cytoplasm of these cells. Listeria monocytogenes and a protein it produces named listeriolysin O (LLO) have strong adjuvant properties that unlike the majority of adjuvants used for cellular based immunotherapies, can be administered after providing an antigen specific treatment or can be used to itself provide antigen-specific treatment when fusing an antigen of interest to an adjuvant protein expressed by the Listeria, such as LLO or an ActA protein.
The present invention addresses this need by providing a combinatorial, multi-target immunotherapeutic approach wherein individual compositions each comprising a recombinant Listeria-strain expressing a different disease-associated antigen than a counterpart Listeria present in a separate composition, are administered separately to a subject having a disease, or the compositions are administered in combination as single bolus administration. The present invention further addresses this need by providing a predetermined number disease-associated antigens or fragments thereof by using a recombinant Listeria expressing at least one fusion protein comprising the antigen fused to an immunogenic Listeria peptide such as an N-terminal LLO, truncated LLO, an ActA protein fragment, or a PEST peptide. Use of such compositions will allow diseases, including tumors, cancers, or others having sub-populations of diseased cells expressing more than one biomarker to be successfully treated.