In case of the chemically conjugated anti-CD30 ADC brentuximab-vedotin (Adcetris), it has been published that full cell killing activity requires release of the payload inside tumor cells via cathepsin B mediated enzymatic cleavage at the valine-citrulline (vc) dipeptide linker, followed by release of free MMAE by self-immolation of the PAB-spacer [4]. Here, CTSB is linked to neoplasm.