The present invention discloses an
antibody drug conjugate of a CLDN 18.2-resistant
antibody. The structure of the
antibody drug conjugate (ADC) is shown as Ab-[(L2)n-L1-D]y in a formula I, wherein Dis a small-molecule
cytotoxic drug, L1 and L2 are connected to the
drug and the antibody separately, and n is 0 or 1; y represents the average number of D which is coupled to Ab, 0 < y <= 10, and Ab is an antibody which can be specifically bound to human CLDN 18.2, and includes a light-chain variable region (VL) and / or a heavy-chain variable region (VH); and the CLDN 18.2-resistant antibody correspondingly contains at least one specific complementary determining region (CDR) sequence or a
mutant sequence of the specific complementary determining region (CDR) sequence in the light-chain variable region (VL) and / or a heavy-chain variable region (VH), and binding of the antibody to CLDN 18.2 is maintained or improved through the
mutation. The invention also discloses a ADC-containing pharmaceutical composition and a preparation method and application of ADC. The
antibody drug conjugate of the antibody has a large security window and low toxic and side effects, and provides more specific,more effective and better treatment option for tumor patients.