PROTAC-linker Conjugate for PAC

PROTAC-linker Conjugate for PAC consist with an antibody conjugated to a PROTAC via a linker. The PROTAC-Antibody Conjugate (PAC) molecules which is antibody conjugated via a linker (L1) to a PROTAC, wherein the PROTAC comprises an ubiquitin E3 ligase binding group, a linker (L2) and a protein binding group. To provide a potent efficacy and a desirable therapeutic index in PAC, the following components are needed. 1. Antibody (Ab): The antibodies in PAC, which are directed against specific antigens on the surface of the cell membrane, will facilitate the efficient targeting of POTAC molecules to the surface of the cell membrane so that they can enter the cell through cytotoxicity. If the antibody in PAC is missing, it is difficult for POTAC molecules to target to the surface of the cell membrane, and they can only enter the cell through cytotoxicity, so the efficiency of PROTAC molecules to enter the cell will be reduced. 2. Linkers (L1): A “linker” (L1) is a bifunctional or multifunctional moiety that can link one or more PROTAC moieties to an antibody (Ab) to form a PAC.