CBO-212

CBO-212 is a first-in-class drug-Fc conjugate (DFC) developed by Cidara Therapeutics using its proprietary Cloudbreak platform. It consists of a small molecule CD73 inhibitor conjugated to a human antibody fragment (Fc). CBO-212 was designed to target CD73 (5'-nucleotidase), an enzyme that converts extracellular adenosine monophosphate (AMP) into adenosine, which acts as a potent immunosuppressor in the tumor microenvironment. By inhibiting both soluble and cell-anchored CD73 and inducing receptor internalization, CBO-212 aimed to restore anti-tumor immune responses in solid cancers. Although it demonstrated significant tumor reduction in preclinical mouse models, development was discontinued in favor of an improved version, CD421 (CBO-421), which features reduced immunogenicity.