P08.03 Neoantigen cancer vaccine auguments anti CTLA-4 efficacy

Background Immunotherapy based on anti CTLA-4 (αCTLA-4) and PD1 (αPD1) is being tested in combination with different therapeutic approaches including other immunotherapy such as neoantigen cancer vaccines (NCV). Here we explored, two murine models, combinations of αCTLA-4 and/or αPD1 a plasmid DNA vaccine expressing neoantigens delivered by electroporation (EP). Materials Methods To evaluate the impact NCV MC38 CT26 tumor model three were generated or without CD4 epitopes. Therapeutic EP protocols large tumors. Flow cytometry was utilized to measure CD8, CD4, T-reg, B cells well neoantigen-specific immune responses, which also measured IFN-γ ELIspot. Results Immune responses augmented αCTLA4 but not significantly impacting growth. Similarly, T cell observed where tumors regressed all mice treated NCV. In line previous evidence, an increased switched memory spleen alone Conclusions These results support use DNA-EP suggest new combined therapy for clinical testing. Disclosure Information F. Palombo: A. Employment (full part-time); Significant; Neomatrix biotech. E. Salvatori: Takis L. Lione: M. Compagnone: Conforti: Evvivax. Aurisicchio: biotech,