Abstract Tyrosine kinase inhibitors (TKIs) that primarily target vascular endothelial growth factor receptors (VEGFRs) are approved to treat several cancers in the metastatic setting. However, improvements in survival for most patients are short-lived and resistance is common. Sequential treatment or ‘switching’ from one VEGFR TKI to another has proven effective following failure in many instances. This may be due to broad drug-specific secondary TKI target profiles that can block metastasis- and angiogenesis-promoting processes. Here we examined sitravatinib (MGDC516), a novel small molecule TKI with activity against VEGFRs, that also can block Met, Axl, and several ephrin receptors (Eph), amongst several others. Transcriptomic and proteomic analysis showed multiple sitravatinib targets upregulated in VEGFR TKI-resistant mouse and human tumor cell lines derived from metastasis in mice. In vitro, sitravatinib treatment decreased proliferation in VEGFR TKI-resistant cells compared to untreated controls, suggesting prior RTKI resistance may enhance sitravatinib anti-tumor potency, while cabozantinib, a multi-targeted RTKI clinically approved after antiangiogenic therapy failure did not demonstrate enhanced anti-proliferative activity in resistant cells. In vivo, sitravatinib treatment significantly reduced orthotopically-implanted primary kidney and breast tumors in mice, with increased effects observed in VEGFR TKI-resistant tumors. Sitravatinib treatment was also found to suppress metastatic disease progression and improve survival in mice when continued after primary tumor removal, indicating metastasis-inhibiting effects of sitravatinib may be enhanced in VEGFR TKI-resistant settings. Together, these studies suggest that broad-spectrum RTKI inhibitors such as sitravatinib that target multiple metastasis-promoting mechanisms improve efficacy after antiangiogenic treatment failure and improve outcomes in a second-line setting. Citation Format: Melissa Dolan, Michalis Mastri, Amanda Tracz, James G. Christensen, Gurkamal Chatta, Yuhao Shi, John M. Ebos. Enhanced efficacy of Sitravatinib (MGCD516) in metastatic models of antiangiogenic therapy resistance [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 326.