Biotransformation Case 2. The second data were from a study where rats were dosed with DAR8 cysteine conjugated ADC, trastuzumab with pyrrolobenzodiazepine (PBD)-dimer payload (SG3584). The data were acquired on a QE HF-X (Thermo Fisher Scientific, Waltham, MA). The data were previously deconvoluted using BioPharma Finder and peaks were manually annotated as described previously. For this ADC, we observed expected biotransformation such as maleimide hydrolysis, but also unexpected peaks that were attributed to sequential linker-payload loss.