Furthermore, LC-HRMS proved to be able to discriminate more readily between subtle changes in DAR compared to the LC-MRM approach as shown in Figure . We hypothesize that the direct DAR analysis using HRMS is more sensitive than the MRM approach which relies on enzymatically released payload as surrogate analyte and measures average DAR indirectly. Importantly, both approaches showed that AZD8205 remained very stable in vivo.