METHODE DE TRAITEMENT DU CANCER DU POUMON NON A PETITES CELLULES RESISTANT A L'EGFR-TKI PAR ADMINISTRATION D'UN CONJUGUE ANTICORPS ANTI-HER3-MEDICAMENT
[Problem] To provide a therapeutic agent and a therapeutic method for EGFR-TKI-resistant non-small cell lung cancer. [Solution] Provided are: a therapeutic agent that contains an anti-HER3 antibody-drug conjugate as an active ingredient; or a therapeutic method characterized by administering an anti-HER3 antibody-drug conjugate.