tb511

TB511 is a first-in-class peptide drug conjugate (PDC) developed to target and eliminate M2-like tumor-associated macrophages (M2-TAMs), which are key contributors to the immunosuppressive tumor microenvironment in solid tumors. The drug consists of a TAM-binding peptide (TAMpep826) that specifically binds to activated CD18, highly expressed on M2-TAMs, and an apoptosis-inducing peptide (dKLA). Upon binding and internalization into M2-TAMs, the dKLA component disrupts mitochondrial membranes, leading to cytochrome c release and apoptosis of these cells. By depleting immunosuppressive M2-TAMs, TB511 enhances anti-tumor immune responses—particularly increasing CD8+ T cell infiltration—and suppresses tumor growth in preclinical models. It is administered as a subcutaneous injection and is currently being evaluated in phase 1/2 clinical trials for advanced solid tumors including colorectal cancer, non-small cell lung cancer, pancreatic ductal adenocarcinoma, and hepatocellular carcinoma[2][3][4][5][7].