| abstract |
A compound of the formula: (i) formula (II): ** Formula ** or a salt or a solvate or a stereoisomer thereof; where: D is a drug residue; T is a remainder of addressing; R1 is hydrogen, unsubstituted or substituted C1-3 alkyl or unsubstituted or substituted heterocyclyl; L1 is a bond, a second autoimmolative linker or a cyclization self-elimination linker; L2 is a link or a second self-immolative linker; wherein if L1 is a second self-immolative linker or a self-elimination cycler linker, then L2 is a link; where if L2 is a second self-immolative linker, then L1 is a link; L3 is a peptide linker; L4 is a link or a spacer; and A is an acyl unit; or (ii) formula (IIa): ** Formula ** or a salt or a solvate or a stereoisomer thereof; where: p is from 1 to 20; D is a drug residue; T is a remainder of addressing; R1 is hydrogen, unsubstituted or substituted C1-3 alkyl or unsubstituted or substituted heterocyclyl; L1 is a bond, a second autoimmolative linker or a cyclization self-elimination linker; L2 is a link or a second self-immolative linker; wherein if L1 is a second self-immolative linker or a self-elimination cycler linker, then L2 is a link; where if L2 is a second self-immolative linker, then L1 is a link; L3 is a peptide linker; L4 is a link or a spacer; and A is an acyl unit. |