INB03 a protein biologic inhibits differentiation and function of MDSC and promotes the immune response to the patient’s tumor in a three-step process:
- Step 1 Inhibition of MDSC: INB03 decreases the number and function of MDSC by inhibiting phosphorylation of STAT3, an intracellular pathway essential for MDSC differentiation and function. By stopping differentiation of MDSC, there are fewer MDSC and fewer immunosuppressive factors produced by MDSC in the tumor microenvironment – a process that decreases the immunosuppressive shield protecting the tumor from the patient’s immune system. Without the immunosuppressive shield protecting the tumor, the patient’s natural killer (NK) and T cells can attack the tumor.
- Step 2 Promotion of NK/DC crosstalk: NK cells and dendritic cells (DC), the central effector cells of the innate immune system that sense cancer as “danger”, bind each other, interact (crosstalk) and reciprocally induce activation and augmentation of their tumoricidal activities and secretion of immunoregulatory cytokines.
- Step 3 Expansion of Immune Response: The interaction and secretion of immunoregulatory cytokines enable NK cells and DC to communicate with the adaptive immune system and promote anti-tumor immune responses. The NK cell/DC crosstalk and immune-regulatory signaling result in stimulation and expansion of the tumor specific CD4+ helper and CD8+ cytotoxic T cell populations that attack and destroy the tumor.
In animal studies, the animals treated with INB03 had smaller and fewer tumors. This resulted in increased survival. We will be starting clinical trials with INB03 in cancer patients soon.