768 Peripheral Pharmacodynamic (PD) Effects of Ociperlimab (OCI) in Combination with Tislelizumab (TIS) in Patients with Advanced Solid Tumors: AdvanTIG-105 Phase 1 Dose-Escalation Study

Background OCI is a humanized monoclonal antibody (mAb) against T-cell immunoreceptor with immunoglobulin and immunoreceptor tyrosine-based inhibitory motif domains (TIGIT) with high affinity and specificity, enabling Fc-mediated effector functions that induce antibody-dependent cellular cytotoxicity. 1 The Phase 1/1b open-label AdvanTIG-105 trial was designed to assess the safety and efficacy of OCI plus TIS (an anti-programmed cell death protein 1 mAb) in patients with advanced solid tumors (NCT04047862). 2 In the dose-escalation part, the combination was well tolerated, and pre-liminary antitumor responses were observed. Here, we report PD biomarker data from peripheral blood. Methods Eligible patients had locally advanced/metastatic, unresectable solid tumors previously treated with standard sys-temic or for which treatment was not available/toler-ated, ECOG PS £ and had received no prior anti-TIGIT Patients received five escalating doses of OCI (50 – 1800mg) intravenously (IV) on Cycle (C) 1