RBN013209

RBN013209 is a potent and selective small molecule inhibitor of the catalytic function of CD38 (ADP-ribosyl cyclase), developed by Ribon Therapeutics. CD38 is an enzyme that converts NAD+ into ADP-ribose (ADPR) or cyclic ADPR (cADPR), and its upregulation is associated with immune suppression in the tumor microenvironment and resistance to immune checkpoint inhibitors (ICIs). By inhibiting both the ecto- and endo-catalytic activities of CD38, RBN013209 prevents the depletion of NAD+ and the accumulation of immunosuppressive metabolites, thereby enhancing T cell fitness and effector function. Preclinical studies have demonstrated single-agent antitumor activity in colon cancer models and synergistic effects when combined with anti-PD-L1 therapy in melanoma models.