Syndax Pharmaceuticals has entered a new clinical collaboration with AstraZeneca to evaluate the safety and efficacy of AstraZeneca’s durvalumab, a human monoclonal antibody directed against programmed death-ligand 1 (PD-L1), in combination with SNDX-6352, Syndax’s monoclonal antibody inhibitor of Colony-Stimulating Factor 1 Receptor (CSF1R), across a variety of solid tumors.

Under the terms of the agreement, Syndax and AstraZeneca will collaborate on a non-exclusive basis to evaluate the combination of the two drugs in multiple solid tumor types. Syndax expects to initiate a Phase Ib study in the first half of 2018 to establish the safety and recommended dose regimen of SNDX-6352 in combination with durvalumab. Data from this study will enable both companies to sponsor, design and initiate subsequent Phase II studies aimed at exploring the safety and efficacy of the combination across a number of defined tumor types.

“It is thought that tumor associated macrophages (TAMs) mediate immunosuppressive effects in the tumor microenvironment, which may limit the benefit of some immunotherapies, including those targeting PD-L1. SNDX-6352 has been shown to reduce the activity of TAMs, which we hope will translate to improved patient outcomes,” said Briggs W. Morrison, M.D., chief executive officer of Syndax. “This collaboration seeks to determine whether SNDX-6352 combined with durvalumab could offer patients a greater benefit than either therapy alone, in specific clinical settings. We look forward to working closely with AstraZeneca to address this important question.”