CD73

Class

Anti-CD73 monoclonal antibody (human IgG1-lambda, triple-mutated Fc for reduced effector function)

Pathway

Blocks CD73-mediated extracellular adenosine production, reversing adenosine-driven immunosuppression

CD73 is an enzyme anchored to the outer surface of cells that converts extracellular AMP, a breakdown product of ATP, into adenosine. In healthy tissue this reaction helps limit excessive inflammation, but tumors frequently exploit the same pathway: dying and stressed cells release large amounts of ATP, and enzymes including CD73 convert it into adenosine within the tumor microenvironment. Adenosine then engages receptors on T cells and other immune cells, dampening their ability to recognize and destroy tumor cells. By blocking CD73's enzymatic activity, antibodies targeting this protein reduce local adenosine production and aim to restore antitumor immune activity, particularly in cancers where the tumor microenvironment is immunosuppressive or where response to other immune-directed therapies has been limited by this pathway. Because CD73 acts on an extracellular substrate, it is accessible to large-molecule antibodies as well as small-molecule enzyme inhibitors, allowing different modalities to achieve the same functional block. This mechanism sits within the broader purinergic signaling pathway that regulates immune tone, tissue repair, and vascular function, so modulating it can carry effects beyond the tumor itself.