Programmable polymeric drugs

A compound having the following structure (I):

• or a stereoisomer, pharmaceutically acceptable salt or tautomer thereof, wherein:
• M at each occurrence, independently has one of the following structures:
• provided that at least one occurrence of M does not have the following structure:
• L is, at each occurrence, independently a nitrogen containing linker;
• L1, L2 and L3 are, at each occurrence, independently an optional alkylene, alkenylene, alkynylene, heteroalkylene, heteroalkenylene, heteroalkynylene or heteroatomic linker;
• R1 is, at each occurrence, independently H, alkyl or alkoxy;
• R2 and R3 are each independently H, OH, SH, alkyl, alkoxy, alkylether, heteroalkyl, —OP(═Ra)(Rb)Rc, Q, or L′;
• 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 has one of the following structures:
• wherein x is halo;
• L′ is, at each occurrence, independently a linker comprising a covalent bond to Q, an antibody or a cell surface receptor antagonist, a linker comprising a covalent bond to an antibody or a cell surface receptor antagonist, a linker comprising a covalent bond to a solid support, or a linker comprising a covalent bond to a solid support residue;
• and
• n is an integer of one or greater.