Syndax Pharmaceuticals has entered a non-exclusive agreement with AstraZeneca to start a Phase Ib trial of durvalumab in combination with SNDX-6352 in the treatment of various solid tumours.

The trial is expected to begin in the first half of this year with the aim to establish the safety and recommended dose regimen of SNDX-6352 and durvalumab combination.

Findings of the trial are anticipated to allow both companies to sponsor, design and initiate subsequent Phase II studies to explore the safety and efficacy of the combination across a number of defined tumour types.

Syndax CEO Briggs Morrison said: “It is thought that tumour-associated macrophages (TAMs) mediate immunosuppressive effects in the tumour 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.

“SNDX-6352 has been shown to reduce the activity of TAMs, which we hope will translate to improved patient outcomes.”

“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.”

Durvalumab is developed by AstraZeneca as a human monoclonal antibody directed against programmed death-ligand 1 (PD-L1).

Syndax’s SNDX-6352 is a monoclonal antibody inhibitor of colony-stimulating factor 1 receptor (CSF1R).

According to Syndax, inhibition of signalling through the CSF-1 receptor has been found to lead to the depletion of tumour associated macrophages (TAMS) cells, which are immuno-suppressive and found in the tumour microenvironment that can inhibit the ability of tumour infiltrating lymphocytes to attack and kill cells.

SNDX-6352 is currently being investigated in a Phase ll multiple ascending dose clinical trial.