S1-S7 all supplementary figures with their legends: S1:Figure S1. OMTX705 binding and internalization in HT1080-WT, -FAP and CAFs S2:Weight change of mice bearing Panc 007, Lung 024 and Breast 014 tumors. S3: OMTX705 Activity in the Immunodeficient Patient Derived Xenografts (PDX) Models of Ovarian Cancer. S4: FAP immunostaining in frozen tumor samples from humanized mice bearing CTG-0860 NSCLC PDX tumor. S5: Separate fluorescent staining of human IgG, Rab7 and nuclei in OMTX705 and OMTX005 treated HT1080-FAP cells (complements the merged image of figure 4C) S6: Immunohistochemical analysis of payload, OMTX005 and OMTX705 distribution in tumors from Panc 007 model. S7: Schematic summary of findings and proposed mechanism of action of OMTX705.