On May 15, 2017 OSE Immunotherapeutics SA (ISIN: FR0012127173; Mnémo: OSE) reported that the Company presented in oral session significant data on Selective Anti-SIRP a OSE-172 (Effi-DEM), at the "2 nd Annual Advances in Immuno-Oncology Congress" in London on May 15, 2017 (Press release, OSE Immunotherapeutics, MAY 15, 2017, View Source [SID1234519637]).

OSE-172 (Effi-DEM) is a humanized monoclonal antibody targeting SIRPa, expressed on suppressive myeloid cells (Myeloid Derived Suppressor Cells, MDSC and Tumor Associated Macrophages, TAM) as well as effector myeloid cells (anti-tumoral macrophages) involved in the Tumor Micro-Environment. As a selective antagonist of SIRPa, OSE-172 promotes recruitment of effector over suppressive myeloid cells, in particular it inhibits M 2 pro-tumorigenic macrophage cells and increases M1 anti-tumorigenic cells, whilst increasing effector memory CD8 T-cells resurrecting key immune defenses.

OSE-172 does not bind to red blood cells and platelets constituting a potential hematologic safety advantage. Moreover OSE-172 i s very selective as it antagonizes SIRPa and does not bind human T-cells (no SIRP- binding, receptor of the SIRP famil y expressed on T-cells), allow ing for a strong human effector T cell proliferation in parallel with a blockade of suppressive myeloid cells. This original mechanism of action provides reduction of tumor growth in various solid tumor models through a straight transformation in the Tumor Micro-Environment: When used as monotherapy or com bined with activators of the T-cell response, anti-PD-L1 (checkpoint inhibitor) and anti-41BB (costimulatory receptor), OSE-172 was very effective allowing effector macrophages and T-cells to work together with significant tumor shrinkage. In parallel with the transformation of suppressive into effector myeloid cells, T umor Micro-Environment was also dramatically modified allowing i ntra-tumoral accumulation of cytolytic natural killer (NK) and of effector B cells. A particular interest is a significant decrease of peripheral regulatory T-cells (suppressive Treg s). " Our myeloid checkpoint inhibitor OSE-172 demonstrate s its strong impact on the Tumor Micro-Environment beyond myeloid cells, tackling cancer through a specific blockade of SIRPa," said Nicolas Poirier, Chief Scientific Officer of OSE Immunotherapeutics. FOR MORE INFOR M ATION ON 2ND ANNUAL ADVANCES IN IMMUNO-ONCOLOGY C ONGRESS View Source 15-16 May 2017, London Session: Discove ry of Immuno-Oncology Therapies: Selective Anti-SIRPa: Next Generation Checkpoint Inhibitor Targeting Pro-Tumors And Suppressors Myeloid Cells Nicolas Poirier, Ph.D., C S O, OSE Immunotherapeutics