Drug conjugate of eribulin derivative, preparation method therefor and application thereof in medicine

An antibody-drug conjugate having a structure of formula (I) or a pharmaceutically acceptable salt or solvate thereof:

• Ab-(L-D)k (I)
• wherein,
• Ab is an antibody or an antigen-binding fragment thereof,
• L is a linker covalently linking Ab to D, and k is 1 to 20,
• -D is shown as in the formula below:
• wherein R1a is selected from the group consisting of hydrogen, alkyl, cycloalkyl, aryl and heteroaryl, and the alkyl, cycloalkyl, aryl and heteroaryl are each independently optionally substituted with one or more substituents selected from the group consisting of alkyl, alkoxy, halogen, deuterium, amino, cyano, nitro, hydroxy, hydroxyalkyl, cycloalkyl, heterocycloalkyl, aryl and heteroaryl, preferably methyl;
• R1b is selected from the group consisting of hydrogen, alkyl, alkoxy, cycloalkyl, aryl and heteroaryl, and the alkyl, cycloalkyl, aryl and heteroaryl are each independently optionally substituted with one or more substituents selected from the group consisting of alkyl, alkoxy, halogen, deuterium, amino, cyano, nitro, hydroxy, hydroxyalkyl, cycloalkyl, heterocycloalkyl, aryl and heteroaryl, preferably hydrogen;
• or R1a and R1b, together with carbon atoms connected thereto, form 5-8 membered heterocycloalkyl, and the heterocycloalkyl is optionally substituted with one or more substituents in alkyl, alkoxy, halogen, deuterium, amino, cyano, nitro, hydroxy, hydroxyalkyl, cycloalkyl, heterocycloalkyl, aryl, and heteroaryl, wherein R1a and R1b are not hydrogen at the same time.