Figure 2

Stability in plasma and in vitro cytotoxicity of ADCs. (a) Stability of ADCs in human plasma. MMAE and ADCs were incubated in plasma for 0–7 days, and free MMAE in plasma was measured (n = 1). MMAE release from both ADCs appeared to be below the lower limit of quantitation for 7 days. (b) MMAE release from ADCs in the absence/presence of IF. Each ADC was incubated in the absence (IF(−)) or presence (IF(+)) of IF with 0.03 nM PA, 150 nM PNG and 100 nM α₂-AP (n = 3). IF-ADC released significantly higher amounts of MMAE on IF-coated plates compared to Control-ADC. Statistical analysis was performed using the Dunnett test. ^†P < 0.05. ^‡P < 0.01. (c) In vitro cytotoxicity of ADCs. Two thousand 5–11 cells were incubated with 0–1.25 mg/mL ADCs and media containing 0.3 nM PA, 1.5 µM PNG and 1.0 µM α₂-AP in the absence/presence of IF (n = 3). IF-ADC was only cytotoxic for 5–11 cells on the IF-coated plate whereas Control-ADC did not exhibit cytotoxicity regardless of the presence or absence of IF.