CD47, an immune checkpoint receptor frequently unregulated in various blood and solid tumors, interacts with ligand SIPR_ on innate immune cells, and conveys a "do not eat me" signal to inhibit macrophage-mediated tumor phagocytosis. This makes CD47 a valuable target for cancer immunotherapy. However, the therapeutic utility of CD47-SIRP_ blockade monoclonal antibodies is largely compromised due to significant red blood cell (RBCs) toxicities and fast target-mediated clearance as a result of extensive expression of CD47 on normal cells. To overcome these limitations and further improve therapeutic efficacy, we designed IBI322, a CD47/PD-L1 bispecific antibody which attenuated CD47 activity in monovalent binding and blocked PD-L1 activity in bivalent binding. IBI322 selectively bound to CD47+PD-L1+ tumor cells, effectively inhibited CD47-SIRP_ signal and triggered strong tumor cell phagocytosis in vitro, but only with minimal impact on CD47 single positive cells such as human RBCs. In addition, as a dual blocker of innate and adaptive immune checkpoints, IBI322 effectively accumulated in PD-L1-positive tumors and demonstrated synergistic activity in inducing complete tumor regression in vivo. Furthermore, IBI322 showed only marginal RBCs depletion and was well tolerated in non-human primates (NHP) after repeated weekly injections, suggesting a sufficient therapeutic window in future clinical development of IBI322 for cancer treatment.

Author Info: (1) Department of Clinical Pharmacology, First Affiliated Hospital of Soochow University, 899 Pinghai Road, Gusu District, Suzhou, 215006, Jiangsu Province, China. NHC Key Laborato

Author Info: (1) Department of Clinical Pharmacology, First Affiliated Hospital of Soochow University, 899 Pinghai Road, Gusu District, Suzhou, 215006, Jiangsu Province, China. NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, 20 Qianrong Road, Binhu District, Wuxi, 214063, Jiangsu Province, China. Institute for Interdisciplinary Drug Research and Translational Sciences, College of Pharmaceutical Sciences, Soochow University, Suzhou, China. (2) Innovent Biologics (Suzhou) Co., Ltd., 168 Dongping Street, Suzhou Industrial Park, Suzhou, 215123, Jiangsu Province, China. (3) Innovent Biologics (Suzhou) Co., Ltd., 168 Dongping Street, Suzhou Industrial Park, Suzhou, 215123, Jiangsu Province, China. (4) Innovent Biologics (Suzhou) Co., Ltd., 168 Dongping Street, Suzhou Industrial Park, Suzhou, 215123, Jiangsu Province, China. (5) Innovent Biologics (Suzhou) Co., Ltd., 168 Dongping Street, Suzhou Industrial Park, Suzhou, 215123, Jiangsu Province, China. (6) Innovent Biologics (Suzhou) Co., Ltd., 168 Dongping Street, Suzhou Industrial Park, Suzhou, 215123, Jiangsu Province, China. (7) Innovent Biologics (Suzhou) Co., Ltd., 168 Dongping Street, Suzhou Industrial Park, Suzhou, 215123, Jiangsu Province, China. (8) Innovent Biologics (Suzhou) Co., Ltd., 168 Dongping Street, Suzhou Industrial Park, Suzhou, 215123, Jiangsu Province, China. (9) Innovent Biologics (Suzhou) Co., Ltd., 168 Dongping Street, Suzhou Industrial Park, Suzhou, 215123, Jiangsu Province, China. (10) Innovent Biologics (Suzhou) Co., Ltd., 168 Dongping Street, Suzhou Industrial Park, Suzhou, 215123, Jiangsu Province, China. (11) Innovent Biologics (Suzhou) Co., Ltd., 168 Dongping Street, Suzhou Industrial Park, Suzhou, 215123, Jiangsu Province, China. (12) NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, 20 Qianrong Road, Binhu District, Wuxi, 214063, Jiangsu Province, China. (13) Department of Clinical Pharmacology, First Affiliated Hospital of Soochow University, 899 Pinghai Road, Gusu District, Suzhou, 215006, Jiangsu Province, China. Institute for Interdisciplinary Drug Research and Translational Sciences, College of Pharmaceutical Sciences, Soochow University, Suzhou, China. (14) NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, 20 Qianrong Road, Binhu District, Wuxi, 214063, Jiangsu Province, China. (15) Department of Clinical Pharmacology, First Affiliated Hospital of Soochow University, 899 Pinghai Road, Gusu District, Suzhou, 215006, Jiangsu Province, China. Institute for Interdisciplinary Drug Research and Translational Sciences, College of Pharmaceutical Sciences, Soochow University, Suzhou, China. (16) NHC Key Laboratory of Nuclear Medicine, Jiangsu Key Laboratory of Molecular Nuclear Medicine, Jiangsu Institute of Nuclear Medicine, 20 Qianrong Road, Binhu District, Wuxi, 214063, Jiangsu Province, China. yangmin@jsinm.org. (17) Department of Clinical Pharmacology, First Affiliated Hospital of Soochow University, 899 Pinghai Road, Gusu District, Suzhou, 215006, Jiangsu Province, China. miaolysuzhou@163.com. Institute for Interdisciplinary Drug Research and Translational Sciences, College of Pharmaceutical Sciences, Soochow University, Suzhou, China. miaolysuzhou@163.com. (18) Innovent Biologics (Suzhou) Co., Ltd., 168 Dongping Street, Suzhou Industrial Park, Suzhou, 215123, Jiangsu Province, China. junjian.liu@innoventbio.com.