PURPOSE: Triple-negative breast cancer (TNBC) is an aggressive disease with limited therapeutic options. Antibodies targeting PD-1/PD-L1 have entered the therapeutic landscape in TNBC, but only a minority of patients benefit. A way to reliably enhance immunogenicity, T cell infiltration, and predict responsiveness is critically needed.EXPERIMENTAL DESIGN: Utilizing mouse models of TNBC, we evaluate immune activation and tumor targeting of intratumoral IL-12 plasmid followed by electroporation (tavokinogene telseplasmid; Tavo). We further present a single arm, prospective clinical trial of Tavo monotherapy in patients with treatment refractory, advanced TNBC (OMS-I140). Finally, we expand these findings using publicly available breast cancer and melanoma data sets.RESULTS: Single cell RNA sequencing of murine tumors identified a CXCR3 gene signature (CXCR3-GS) following Tavo treatment associated with enhanced antigen presentation, T cell infiltration and expansion, and PD-1/PD-L1 expression. Assessment of pre- and post-treatment tissue from patients confirms enrichment of this CXCR3-GS in tumors from patients that exhibited an enhancement of CD8+ T cell infiltration following treatment. One patient, previously unresponsive to anti-PD-L1 therapy, but who exhibited an increased CXCR3-GS after Tavo treatment, went on to receive additional anti-PD-1 therapy as their immediate next treatment after OMS-I140, and demonstrated a significant clinical response.CONCLUSIONS: These data show a safe, effective intratumoral therapy that can enhance antigen presentation and recruit CD8 T cells, which are required for the anti-tumor efficacy. We identify a Tavo treatment-related gene signature associated with improved outcomes and conversion of non-responsive tumors, potentially even beyond TNBC.
View details for DOI 10.1158/1078-0432.CCR-20-3944
View details for PubMedID 33593880