These findings identify CLEVER-1+ TAMs as both biomarker and functional mediator of anti-PD-1 therapy resistance, providing a rationale for combining bexmarilimab with immune checkpoint blockade in GC. In this commentary, we discuss the mechanistic significance, translational potential, and clinical prospects of CLEVER-1 blockade to overcome immunotherapy resistance in GC.
The humanized anti-Clever-1 IgG4 antibody, bexmarilimab, is under clinical investigation for treating solid tumors (NCT03733990) and hematological malignancies (NCT05428969)... These findings identify sClever-1 as a previously unrecognized, immunosuppressive mediator in cancer that operates independently of cellular Clever-1 expression. sClever-1 may serve as both a therapeutic target and biomarker to guide immunotherapy strategies.
Hepatic melanoma metastases show resistance to Stabilin-1 targeting approaches. This suggests that anti-Stab1 therapies should be considered with respect to the tumor entity or target organs.
Spatial transcriptomics profiling of DC and non-DC tumors demonstrates bexmarilimab-induced macrophage activation and stimulation of IFNγ and T cell receptor signaling selectively in DC patients. These data suggest that bexmarilimab therapy is well tolerated and show that macrophage targeting can promote immune activation and tumor control in late-stage cancer.
We further showed that bexmarilimab was most efficacious in macrophages with low baseline IFN signaling, as chronic IFNγ priming abolished bexmarilimab-induced TNFα release. These results highlight an approach to target immunologically cold tumors and to increase the likelihood of their subsequent response to immune checkpoint inhibitors.