US Patent 10383878 Anti-HER3 antibody-drug conjugate

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: -L1-L2-LP-NH—(CH2)n1-La-(CH2)n2-C(═O)— or -L1-L2-LP- (the anti-HER3 antibody is connected to the terminal of L1, the antitumor compound is connected to the carbonyl group of —(CH2)n2-C(═O)— moiety or the C terminal of LP, with the nitrogen atom of the amino group at position 1 as a connecting position).