CS5005

CS5005 is a first-in-class antibody-drug conjugate (ADC) targeting somatostatin receptor 2 (SSTR2). It is designed to selectively eliminate SSTR2-positive tumors, including small cell lung cancer (SCLC), neuroendocrine carcinoma (NEC), and neuroendocrine tumors (NETs). The ADC consists of CStone’s proprietary high-affinity, high-selectivity anti-SSTR2 monoclonal antibody, a hydrophilic β-glucuronide linker, and a potent topoisomerase I inhibitor payload—specifically Exatecan. Preclinical studies have shown that CS5005 demonstrates strong antigen-dependent cytotoxicity against tumor cells in vitro and robust tumor growth inhibition in vivo. The drug exhibits superior stability due to its proprietary linker technology and has favorable pharmacokinetic properties. Importantly, its antitumor activity is not compromised by co-administration with other SSTR2-targeted therapies such as octreotide or Lutathera. CS5005 is being developed by CStone Pharmaceuticals for the treatment of SSTR2-positive malignancies[1][3][4][5].