#$%^&*AU2020200227A120200206.pdf#####ABSTRACT To provide an antitumor drug having excellent therapeutic effect, which is excellent in terms of antitumor effect and safety. Provided is an antibody-drug conjugate in which an antitumor compound represented by the following formula is conjugated to an anti-HER3 antibody via a linker having a structure represented by the formula: -L-L2-LP-NH-(CH2)n-La(CH2)n2_ C(=0)- or -L1-L2 -Lp- (the anti-HER3 antibody is connected to the terminal of L', the antitumor compound is connected to the carbonyl group of -(CH2)n 2-C(=)- moiety or the C terminal of LP, with the nitrogen atom of the amino group at position 1 as a connecting position).
