A phase Ia/Ib trial of tislelizumab, an anti-PD-1 antibody (ab), in patients (pts) with advanced solid tumors

Background: Tislelizumab, a humanized IgG4 monoclonal Ab with high affinity and specificity for PD-1, was engineered to minimize binding to FcγR on macrophages, thus abrogating antibody-dependent phagocytosis, a mechanism of T-cell clearance and potential resistance to anti-PD-1 therapy. Previous reports from this first-in-human study (NCT02407990), and other early phase studies, suggested tislelizumab was generally well tolerated and had antitumor activity in pts with advanced solid tumors. Here we report the effects of tislelizumab in a subset of pts enrolled in phase 1A/1B.