OAT-1746

OAT-1746 is a novel, potent, and selective **oral small molecule inhibitor** of **Arginase 1 and 2 (ARG1/2)** with reported IC50 values of approximately 20 nM for human ARG1 and 39 nM for human ARG2. It is designed to **increase arginine levels** and **modulate the tumor microenvironment**, thereby potentiating antitumor immune responses. In preclinical studies, OAT-1746 restored T-cell proliferation suppressed by tumors, reduced the proportion of regulatory T cells, and synergized with immune checkpoint inhibitors, such as anti-PD-1 therapies. Alone, its antitumor effect was modest, but it demonstrated enhanced efficacy as part of multi-agent immunotherapy regimens. OAT-1746 is orally bioavailable and exhibits low toxicity at therapeutically relevant concentrations.