The invention provides antibody-drug conjugates comprising an antibody conjugated to a pyrrolobenzodiazepine drug moiety via a disulfide linker, pyrrolobenzodiazepine linker-drug intermediates, and methods of using the antibody-drug conjugates.本發明提供包含經由二硫鍵連接子結合於吡咯并苯并二氮呯藥物部分之抗體的抗體-藥物結合物、吡咯并苯并二氮呯連接子-藥物中間物及使用該等抗體-藥物結合物之方法。