SNDX-6352 is an IgG4 humanized monoclonal antibody that binds to the ligand binding domain of the CSF-1 receptor, blocking the binding and consequent activation by both natural ligands (IL-34 and CSF-1). CSF-1R is expressed on the surface of specific immuno-suppressive cells (e.g., tumor associated macrophages or TAMs) known to play a role in the growth, survival, and metastases of cancer. Inhibition of the CSF-1 receptor is thought to disrupt the activity of TAMs, resulting in a decrease in the immunosuppressive environment immediately surrounding the tumor, or tumor micro-environment. This mode of action is thought to make CSF-1R inhibitors well suited for use in combination with checkpoint inhibitors, particularly in cancers where there may be limited activity of checkpoint inhibitors as monotherapy.

As a class, CSF-1R inhibitors have shown promising preclinical activity in a variety of tumor types. Based on the encouraging preclinical data observed to date, multiple CSF-1R agents are currently being investigated in various clinical trials in combination with checkpoint inhibitors as well as with chemotherapies.

We look forward to initiating a broad clinical development program for SNDX-6352 both as monotherapy and in combination with other oncology agents, including checkpoint inhibitors and entinostat.