Programmable polymeric drugs

A compound having the following structure (IA):

• or a stereoisomer, pharmaceutically acceptable salt or tautomer thereof, wherein:
• M is, at each occurrence, independently a biologically active moiety selected from an NSAID, a kinase inhibitor, an anthracycline, an EGFR inhibitor, an alkylating agent, and anti-cancer drug;
• or a fluorescent dye, provided at least one occurrence of M is not a fluorescent dye;
• L is a physiologically cleavable linker;
• L2 and L3 are, at each occurrence, independently absent or an alkylene, alkenylene, alkynylene, heteroalkylene, heteroalkenylene, heteroalkynylene or heteroatomic linker;
• L4 is, at each occurrence, independently an alkylene, alkenylene, alkynylene, heteroalkylene, heteroalkenylene or heteroalkynylene linker;
• R1 is, at each occurrence, independently H, alkyl or alkoxy;
• R2 and R3 are each independently OH, SH, alkyl, alkoxy, alkylether, heteroalkyl, —OP(═Ra)(Rb)Rc, Q, or a protected form thereof, or L′;
• R4 is, at each occurrence, independently OH, SH, O−, S−, ORd or SRd;
• R5 is, at each occurrence, independently oxo, thioxo or absent;
• Ra is O or S;
• Rb is OH, SH, O−, S−, ORd or SRd;
• Rc is OH, SH, O−, S−, ORd, OL′, SRd, alkyl, alkoxy, heteroalkyl, heteroalkoxy, alkylether, alkoxyalkylether, phosphate, thiophosphate, phosphoalkyl, thiophosphoalkyl, phosphoalkylether or thiophosphoalkylether;
• Rd is a counter ion;
• Q is, at each occurrence, independently a moiety comprising a reactive group, or protected form thereof, capable of forming a covalent bond with a complementary reactive group Q′ on a targeting moiety;
• L′ is, at each occurrence, independently a linker comprising a covalent bond to Q, a targeting moiety, a linker comprising a covalent bond to a targeting moiety, a linker comprising a covalent bond to a solid support, a linker comprising a covalent bond to a solid support residue, a linker comprising a covalent bond to a nucleoside or a linker comprising a covalent bond to a further compound of structure (IA);
• m is, at each occurrence, independently an integer of zero or greater;
• and
• n is an integer of one or greater.