Stability of cAC10-vcMMAE drug linkage in plasma. cAC10-vcMMAE at 0.327 mg/mL (containing 10 μg/mL MMAE) was incubated in human, mouse, or dog plasma at 37°C over a period of 10 days. Aliquots were taken at the indicated time points and analyzed by LCMS/MS for free drug, as described in “Materials and methods.” The percentage released free drug relative to an experimental maximum was plotted versus the incubation time in days. Error bars indicate ± SD.