Polymer linkers and their uses

A compound of Formula (I) comprising block repeat block monomer (b):

• wherein
• L1 is a linking group selected from alkylene, heteroalkylene, cycloalkylene, heterocyclylene, arylene, heteroarylene, amidoalkylene, amidoheteroalkylene, and any combination thereof;
• L2 is absent, or can be of the formula:
• L2A is a linking group selected from alkylene, heteroalkylene, cycloalkylene, heterocyclylene, arylene, heteroarylene, —C(O)—, —NRc—, and any combination thereof;
• L2B and L2C are independently absent or a linker group selected from alkylene, heteroalkylene, cycloalkylene, heterocyclylene, arylene, heteroarylene, amidoalkylene, amidoheteroalkylene, —C(O)—, —NRc—, and any combination thereof;
• B2A and B2B are independently absent or a cleavable linker;
• T is a therapeutic agent selected from the group consisting of chemotherapeutic agents, microtubule inhibitors, DNA-damaging agents and RNA transcription inhibitors, and block repeat block monomer (d):
• wherein
• L3 is a linker group selected from alkylene, heteroalkylene, cycloalkylene, heterocyclylene, arylene, heteroarylene, amidoalkylene, amidoheteroalkylene, and any combination thereof;
• Re is a substituent selected from hydrogen, alkyl and heteroalkyl;
• L4 is a group of the formula:
• L4A is a linker group selected from alkylene, heteroalkylene, cycloalkylene, heterocyclylene, arylene, heteroarylene, —C(O)—, —NRc—, and any combination thereof;
• L4B and L4C are independently absent or a linker group selected from alkylene, heteroalkylene, cycloalkylene, heterocyclylene, arylene, heteroarylene, amidoalkylene, amidoheteroalkylene, —C(O)—, —NRc—, and any combination thereof;
• B4A and B4B are independently absent or a cleavable linker;
• C4A is a group selected from
• where
• A is —H or a targeting moiety selected from the group consisting of an antibody, a synthetically functionalized antibody, a peptide and a targeting ligand;
• “n” is independently at each occurrence an integer ranging from 0-5;
• each cleavable linker B2A, B2B, B4A and B4B, if present, is independently selected from —S—S—, —C(═O)O—, —OC(═O)—, —C(═O)NRc—, —N(Rc)C(═O)—, —OC(═O)O—, —NRcC(═O)O—, —OC(═O)N(Rc)— or —N(Rc)C(═O)N(Rd)—, —C(═O)N(Rc)C(═O)—, —C(═O)S—, —SC(═O)—, —SC(═O)S—, —OC(═O)S—, —SC(═O)O—, —OC(═S)O—, —SC(═S)S—, —N(Rc)SO2—, —SO2N(Rc)—, —N(Rc)SO2N(Rd)—, —C(═O)N(Rc)N(Rd)—, —N(Rc)N(Rd)C(═O)—, —N(Rc)N(Rd)C(═O)O—, —OC(═O)N(Rc)N(Rd)—, —C(Rc)═N—NH—C(═O)—, —C(═O)NH—N═C(Rc)—, —C(Rc)═N—O—, —O—N═C(Rc)—,
• Rc and Rd are independently selected at each occurrence from hydrogen, alkyl, heteroalkyl, cycloalkyl, and heterocyclyl.