PROBLEM TO BE SOLVED: To provide an antigen binding molecule, a pharmaceutical composition comprising the antigen binding molecule and a production method thereof, where the binding molecule has such functions that when it binds to an antigen, it enhances uptake of the antigen into a cell, it can bind a larger number of antigen per molecule, it has improved pharmacokinetics, and it accelerates intracellular dissociation of the antigen to which it has bound outside the cell, it is released in a free state from the cell, thereby reducing the total or free antigen concentration in the serum.SOLUTION: A pharmaceutical composition comprises an antigen binding molecule comprising an antigen binding domain and an Fcγ receptor binding domain, where the antigen binding domain has a binding activity to a human FcRn under acidic pH conditions and whose antigen binding activity changes according to the ionic concentration, and the Fcγ receptor binding domain has a higher Fcγ receptor binding activity under neutral pH conditions, compared with the Fcγ receptor binding domain of a naturally occurring human IgG Fc region in which the sugar chain at position 297 by EU numbering is a fucose-containing sugar chain.SELECTED DRAWING: None【課題】結合する抗原の細胞内への取込が促進され、一分子当りの結合できる抗原の数が増加し、薬物動態が改善され、かつ、細胞外で結合した抗原を細胞内で解離することが促進され、抗原と結合していない状態での細胞外への放出が促進され、血漿中の総抗原濃度または遊離抗原濃度を減少させる機能を有する抗原結合分子、および、当該抗原結合分子を含む医薬組成物、およびそれらの製造方法の提供。【解決手段】pH酸性域の条件下でヒトFcRnに対する結合活性を有し、イオン濃度の条件によって抗原に対する抗原結合分子の結合活性が変化する抗原結合ドメイン、およびpH中性域の条件下で、EUナンバリング297位に結合した糖鎖がフコース含有糖鎖である天然型ヒトIgGのFc領域のFcγレセプターに対する結合ドメインよりもFcγレセプターに対する結合活性が高いFcγレセプター結合ドメインを含む抗原結合分子を含む医薬組成物。【選択図】なし
