A Conjugate having formula IV: L - (LU-D) P (IV) or a pharmaceutically acceptable salt or solvate thereof； wherein L is a Ligand Unit selected from the group consisting of an antibody and an antigen-binding fragment of an antibody, LU is a Linker Unit, p is 1 to 20； and D is selected from the group consisting of D1 to D6 having the structures as defined in claim 1 and wherein LU is: wherein the asterisk indicates the point of attachment to D, the wavy line indicates the point of attachment to the Ligand Unit, Y is NH and E is glucuronic acid； and A 1 is a Stretcher Unit.
