Bispecific antibodies in cancer therapy:Target selection and regulatory requirements

In recent years,the development of bispecific antibodies(bsAbs)has been rapid,with many new structures and target combinations being created.The boom in bsAbs has led to the successive issuance of industry guidance for their development in the US and China.However,there is a high degree of similarity in target selection,which could affect the development of diversity in bsAbs.This review presents a classification of various bsAbs for cancer therapy based on structure and target selection and examines the advantages of bsAbs over monoclonal antibodies(mAbs).Through database research,we have identified the preferences of available bsAbs combinations,suggesting rational target selection options and warning of potential wastage of medical resources.We have also compared the US and Chinese guidelines for bsAbs in order to provide a reference for their development.

Novel phthalimides regulating PD-1/PD-L1 interaction as potential immunotherapy agents

Programmed cell death 1(PD-1)/programmed cell death ligand 1(PD-L1)have emerged as one of the most promising immune checkpoint targets for cancer immunotherapy.Despite the inherent advantages of small-molecule inhibitors over antibodies,the discovery of small-molecule inhibitors has fallen behind that of antibody drugs.Based on docking studies between small molecule inhibitor and PD-L1 protein,changing the chemical linker of inhibitor from a flexible chain to an aromatic ring may improve its binding capacity to PD-L1 protein,which was not reported before.A series of novel phthalimide derivatives from structure-based rational design was synthesized.P39 was identified as the best inhibitor with promising activity,which not only inhibited PD-1/PD-L1 interaction(IC_(50)=8.9 nmol/L),but also enhanced killing efficacy of immune cells on cancer cells.Co-crystal data demonstrated that P39 induced the dimerization of PD-L1 proteins,thereby blocking the binding of PD-1/PD-L1.Moreover,P39 exhibited a favorable safety profile with a LD_(50)>5000 mg/kg and showed significant in vivo antitumor activity through promoting CD8^(+)T cell activation.All these data suggest that P39 acts as a promising small chemical inhibitor against the PD-1/PD-L1 axis and has the potential to improve the immunotherapy efficacy of T-cells.