Abstract 3090: LY3207447, a tetravalent bispecific antibody targeting VEGFR2 and angiopoietin-2, provides a more efficient anti-angiogenic therapy and an alternative for combination

Angiopoietin-2 (Ang-2) 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. In tumors, Ang-2 is up-regulated and acts together with the VEGF/VEGFR2 pathway to stimulate tumor angiogenesis and metastasis. While therapeutic intervention using antagonists to the VEGF/VEGFR2 pathway has proven to be successful in limiting disease progression in a number of different clinical settings, there is an obvious need for an improved response. In various preclinical mouse angiogenesis or xenograft models, the combination treatment with anti-Ang2 antibody and the VEGF/VEGFR blocker provided additional benefit over inhibiting the individual pathway. Here as an alternative to combo therapy, we have engineered a tetravalent IgG-scFv bispecific antibody, LY3207447. LY3207447 is an immunoglobulin G4 (IgG4) antibody, comprising of VEGFR2 antibody derived from ramucirumab and a C-terminally fused single-chain variable fragment (scFv) targeting Ang2. LY3207447 binds to both the extracellular domain of VEGFR2 and soluble Ang2 with high affinity and blocks binding of Ang2 to Tie2 and VEGF to VEGFR2, and therefore inhibits signaling. We have shown that LY3207447 blocks binding of human Ang-2 to human Tie2-Fc by an ELISA assay and neutralizes Ang-2 induced phospho-Tie-2, but not Ang-1 induced phospho-Tie-2 in CHO cells overexpressing Tie-2 receptor. Moreover, LY3207447 neutralizes human VEGF165-induced phospho-VEGFR2 stimulation, cord formation and cell proliferation in human endothelial colony forming cells (ECFCs) and human dermal microvascular endothelial cells (HMVEC-d). LY3207447 blocks human and cyno VEGFR2, but not rodent VEGFR2. For anti-Ang2 arm, LY3207447 blocks human, cyno and mouse Ang2. Pre-clinical evaluation of LY3207447 in mouse retinal angiogenesis model resulted in an abrogation of angiogenesis. Combination studies using a rodent-specific surrogate VEGFR2 blocking antibody, DC101, with parental Ang2 antibody from which the scFv was derived from, inhibited both tumor growth and metastasis, resulting in increased survival compared to monotherapies in mouse xenograft model. These data establish VEGFR2/Ang2 bispecific antibodies as a promising anti-angiogenic, anti-metastatic and anti-tumor agent for the treatment of cancer in combination with other therapies. Citation Format: Jonathan Tetreault, Sudhakar Chintharlapalli, Donmienne Leung, Damien Gerald, Linda Lee, Rowena Almonte-Baldonado, Lysiane Huber, Jianghuai Xu, Bharathi Ramamurthy, Jennifer Pereira, Johnny Croy, Jirong Lu, Ling Liu. LY3207447, a tetravalent bispecific antibody targeting VEGFR2 and angiopoietin-2, provides a more efficient anti-angiogenic therapy and an alternative for combination [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2017; 2017 Apr 1-5; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2017;77(13 Suppl):Abstract nr 3090. doi:10.1158/1538-7445.AM2017-3090