Enhancing Tumor-Immune Response with Combined IL-12 Gene Therapy and CXCL9 Intratumoral Electroporation

Clinical and preclinical evidence has shown that intratumoral delivery of plasmid IL-12, also known as TAVO, through electroporation can stimulate IFN-γ production and T cell recruitment within the tumor microenvironment, leading to sustained systemic T cell responses. Analysis of biomarker data from a clinical trial combining IL-12 with anti-PD-1 treatment revealed a correlation between clinical responses and the levels of intratumoral CXCR3. Patients who responded to the treatment exhibited a significant increase in intratumoral CXCR3 transcripts post-treatment.

Given the role of the IFN-γ/CXCL9/CXCR3 pathway in enhancing sensitivity to anti-PD-1 therapies, the hypothesis was that the combination of intratumoral TAVO with a DNA-encoded CXCL9 would boost this pathway and enhance the anti-PD-1 response. The establishment of an appropriate CXCL9 gradient is suggested to effectively regulate the presence of tumor-infiltrating CXCR3+ T cells.

Previous work has shown that the intratumoral electroporation of plasmid IL-12 and CXCL9 can elicit a potent antitumor immune response, increasing systemic antigen-specific CD8+ T cells and leading to the regression of both treated and untreated tumors. The current study builds on these findings, demonstrating that an intensified CXCL9 gradient via intratumoral electroporation effectively directs CXCR3+ CD8+ T cells into tumors.

Further investigation into the synergistic potential of DNA-encodable IL-12 and CXCL9 showed that intratumoral TAVO rapidly increases the population of CXCR3+ CD8+ T cells in the lymph node, and their depletion negates the IL-12-mediated anti-tumor effect. Additionally, the electroporation of IL-12 and CXCL9 led to a transcriptomic enrichment within the tumor microenvironment associated with immune-related pathways, antigen presentation, and TCR signaling, indicating a strengthened anti-tumor immune response.

Finally, using a partially responsive anti-PD-1 tumor model, the study demonstrated that the combination of intratumoral electroporation of plasmid IL-12 with CXCL9 significantly improves the response to anti-PD-1 treatment. This provides a compelling basis for the development of an Investigational New Drug application for this intratumoral DNA-encodable combination therapy.