Genocea Biosciences, Inc. presented four posters that collectively validate the company’s unique and differentiated approach to identifying clinically meaningful immunotherapy targets at The Society for Immunotherapy of Cancer (SITC) 35th Anniversary Annual Meeting taking place virtually November 9 – 14. In follow up to data shared at the European Society for Medical Oncology (ESMO) Virtual Congress 2020, the company shared expanded clinical and immunogenicity findings from Part B of its ongoing GEN-009 Phase 1/2a trial, which evaluates GEN-009, the company’s neoantigen vaccine, in combination with PD-1 inhibitors in advanced cancers. Posters 390 and 413 outline the clinical and immune responses elicited by GEN-009 in 16 checkpoint inhibitor (CPI) therapy sensitive and resistant patients. Poster 413 was a highly scored abstract selected for a Poster Walk. Of the nine CPI-sensitive patients, three patients experienced a novel reduction in tumor volume post-GEN-009 dosing and achieved independent RECIST responses after vaccination, including 2 PRs and 1 CR. Five additional CPI-sensitive patients have shown disease control post-vaccination for up to 11 months. Within the CPI-resistant population, five of seven patients appear to have stabilized disease lasting up to seven months. GEN-009 elicited strong anti-tumor immune responses with both CD4+ and CD8+ T cell responses observed at day 50 post-vaccination and with peak ex vivo responses occurring Day 92. Early data from two patients tested so far show a complete absence of circulating tumor DNA by day 50, which is consistent with a vaccine clinical effect. There was also emerging evidence of epitope spreading in patients who successfully responded to therapy. GEN-009 was safe and well tolerated.