STI-5171

STI-5171 is a fully human monoclonal antibody that specifically targets CD38 (ADP-ribosyl cyclase/cyclic ADP-ribose hydrolase 1), a cell surface protein highly expressed in various hematological malignancies, most notably multiple myeloma. Discovered using the Sorrento G-MAB library, STI-5171 exhibits high binding affinity and specific internalization into CD38-positive cells. While it possesses intrinsic properties typical of anti-CD38 antibodies, its primary clinical application is as the targeting component of the antibody-drug conjugate (ADC) STI-6129 (also known as CD38-077), where it is conjugated to the microtubule inhibitor duostatin-5.2. STI-5171 has demonstrated the ability to bind to tumor cells isolated from patients who are refractory to daratumumab, suggesting potential utility in resistant populations.