CStone Pharmaceuticals announced that the investigational new drug (IND) application of multi-specific antibody CS2006/NM21-1480 has been approved by the National Medical Products Administration (NMPA) of China. CS2006/NM21-1480 represents a leading class of next-generation anti-PD-1/PD-L1 cancer immunotherapies and a new backbone molecule for combinations. CS2006/NM21-1480 is a monovalent, tri-specific antibody-based molecule targeting PD-L1, 4-1BB, and human serum albumin (HSA). CS2006/NM21-1480 is designed to bind to the immune co-stimulation receptor 4-1BB and conditionally activate T cells only when engaging the checkpoint receptor ligand PD-L1 on the surface of tumor cells, potentially preventing the liver toxicities observed with previous anti-4-1BB agonistic antibodies. As a potential best-in-class drug, CS2006/NM21-1480 could be used as monotherapy or in combination with multiple treatments. The upcoming clinical study is designed to evaluate the safety, pharmacokinetics, and anti-tumor efficacy of CS2006/NM21-1480 in Chinese patients with various advanced solid tumors. Compared to other PD-L1/4-1BB bispecific antibody candidates, CS2006/NM21-1480's unique monovalent structure and ultra-high-affinity PD-L1-binding is designed to fully exploit the synergistic potential of tumor-localized modulation of PD-L1 and 4-1BB, to provide broader and more sustained treatment response and at the meantime, to avoid systemic toxicities. Furthermore, half-life extension via the HSA-binding motif enables convenient dosing schedules for patients. CS2006/NM21-1480 is anticipated to be effective against tumors with a wide range of PD-L1 expression levels and may overcome primary and/or acquired resistance to anti-PD-1/PD-L1 therapies.