Triggering Receptor Expressed on Myeloid Cells (TREM)-Like Transcript 1 (TLT-1), a novel innate immune checkpoint protein secreted exclusively from activating platelets, has been shown to mediate immune suppression within the tumor microenvironment. Interestingly, our data indicated that TLT-1 is highly enriched in cancers that are resistant to current immune checkpoint inhibitors. Furthermore, the expression level of TLT-1 is correlated with overall survival rate in cancer patients.

Blockage of the binding of TLT-1 to its receptor by ASD141 monoclonal antibody is a safe therapeutic strategy for the remission of pathologic conditions because the absence of TLT-1 receptor signals in gene-engineered mouse has no effects on the normal health condition.

Our animal pharmacological studies demonstrated that ASD141 disrupted the immune-suppressive microenvironment in