An ADC against SEMA4A is potent in vivo. (A) Xenograft model to test in vivo efficacy of 5E3-vedotin. Mice were injected with MM1.S-luciferase or JK-6L luciferase cells by tail vein injection at day −13 and established disease confirmed by luciferase intensity, measured by using an in vitro imaging system. 5E3-vedotin was injected via the tail vein at 4 mg/kg twice weekly for a total of 4 doses on days 0, 2, 6, and 9. Controls were trastuzumab-vedotin (isotype; TRA-vedotin) and nonconjugated 5E3 antibody. Mice were imaged weekly and at euthanasia. (B) Luciferase intensity in the regions of interest (ROI) of the JK-6L model before dosing, exhibiting similar disease dissemination levels between treatment and control arms. (C) Time course of luciferase intensity for the same study as in panel B. ROI intensity was normalized to the baseline ROI (week 0) for each mouse. (D) Luciferase intensity in the ROI of the MM1.S model before dosing. (E) Time course of luciferase intensity for the same study as in panel D. ROI intensity was normalized to the baseline ROI (week 0) for each mouse. (F) Images of luciferase intensity of the MM1.S model. (G) Kaplan-Meier curve for the MM1.S model comparing survival of mice in the 5E3-vedotin treatment group vs that of mice in the control groups. Survival was significantly increased in the treatment group compared with isotype control (Cox proportional hazards model, P = .0004). Error bars are ±SD.