Angiopoeitin-2 (Ang2) is released from endothelial cells only in response to stimulus (e.g. wound healing, tumor growth) and facilitates blood vessel sprouting and inhibits pericyte-endothelial cell interaction via Tie2 signaling. Combination of an anti-Ang2 antibody and aflibercept, a VEGF trap, has been shown to inhibit tumor growth and decrease tumor vascularity in mouse xenograft tumor models (Daly et al., Cancer Res (2013) 73(1):108). Multiple investigational anti-Ang2 antibody therapies are currently in clinical trials. LY3127804 is a humanized and engineered IgG4 isotype antibody that selectively binds to Ang2 with high affinity and neutralizes Ang2 induced phospho-Tie2. LY3127804 inhibits sprouting angiogenesis and increases pericyte coverage in a mouse developmental retinal angiogenesis model and in mice bearing PC3 xenograft tumors. Combination of LY3127804 and DC101, a potent anti-VEGFR2 antibody, exhibits enhanced efficacy when compared to monotherapy in multiple patient derived xenograft models including NSCLC and ovarian cancers. Anti-Ang2 antibody monotherapy alone resulted in marginal reduction of tumor growth and improved overall survival, while DC101monotherapy had greater reduction in tumor volume with no survival benefit in MDA-MB-231 breast orthotopic model. Combination of anti-Ang2 antibody with anti-VEGFR2 antibody shows reduction in tumor volume and improved overall survival. This robust pre-clinical evidence supports testing the combination of anti-Ang2 and anti-VEGFR2 antibodies in the clinic. LY3127804 is currently in Phase 1 clinical trials (NCT02597036) Citation Format: Sudhakar R. Chintharlapalli, Johnny E. Croy, Donmienne Leung, Damien Gerald, Jirong Lu, Philip W. Iversen, Linda N. Lee, Lysiane Huber, Jonathan Tetreault, Rowena Almonte-Baldonado, Jianghuai Xu, Bharathi Ramamurthy, Jennifer A. Pereira, Chi-Kin Chow, Axel-Rainer Hanauske, Volker Wacheck, Laura Benjamin, Ling Liu. LY3127804, a novel anti-Angiopoietin-2 antibody in combination with an anti-VEGFR2 antibody potently inhibits angiogenesis, tumor growth and metastasis. [abstract]. In: Proceedings of the 107th Annual Meeting of the American Association for Cancer Research; 2016 Apr 16-20; New Orleans, LA. Philadelphia (PA): AACR; Cancer Res 2016;76(14 Suppl):Abstract nr 3259.