Evaluation of the in vivo efficacy of anti-ICOS-MMAE ADCs in a mouse xenograft model with MyLa cells. (A) Twenty-one mice were engrafted with 8.10⁶  MyLa cells each, which were subcutaneously injected with 200 μL phosphate-buffered saline and no basement membrane matrix. Mice were then randomly assigned to 3 groups and monitored for tumor volume after 2 treatments of anti-HER-2, anti-CD30, or anti-ICOS ADCs administered 4 days apart (days 10 and 14 after engraftment). (B) OS curves (Kaplan-Meier) comparing the effect of anti-ICOS and anti-CD30 ADCs. The difference between the 2 curves is significant (P = .0006). (C-E) Detection of the development of bioluminescent MyLa metastases in 26 mice assigned to 3 groups and treated with anti-HER2, anti-CD30, or anti-ICOS ADCs in lungs (C), spleen (D), and liver (E). (F) Images of living mice scanned with a luminometer following treatment with anti-HER2, anti-CD30, or anti-ICOS ADCs. At day 40, subcutaneous recurrence was detected in the anti-CD30 ADC group (arrow). ***P < .001. D, day.