Drugs

SG (hRS7-CL2A-SN-38), non-targeting control ADC (h679-CL2A-SN-38), and unconjugated antibody hRS7 IgG were obtained from Immunomedics, Inc. (Morris Plains, NJ). SG and control ADC were dissolved in sterile 0.9% sodium chloride as a 2 μM stock solution for the in vitro experiments. Drug-to-antibody ratio (DAR) of SG and control ADC was 6.78 and 6.84, respectively. For the in vitro experiments, the dosage of the drug was adjusted according to the DAR, in order to expose equivalent quantities of SN-38 cells treated with SG and control ADC. In in vivo experiments, SG and control ADC were dissolved in sterile 0.9% sodium chloride as a 5 mg/mL solution. hRS7 IgG (molecular weight: 150 kDa) was obtained in liquid form from Immunomedics, Inc. as a 10 mg/mL solution.