IO Biotech, Inc. shared new data related to the company?s lead therapeutic cancer vaccine candidate, IO102-IO103, at the American Association for Cancer Research (AACR) Annual Meeting 2024, taking place April 5-10, 2024, in San Diego, California. The data presented in the AACR poster are from two different animal tumor models and show that vaccines targeting IDO1 and PD-L1 expressing cells can cooperatively reduce tumor growth with each contributing to the anti-tumor effect through distinct molecular pathways. Where high levels of IDO1 and PD-L1 expression were seen in the tumor microenvironment (TME), the IDO1 vaccine predominantly reduced myeloid-derived immune suppression, while the PD-L1 vaccine enhanced anti-tumor T-effector functions.

In contrast, where IDO1 and PD-L1 expression was lower, the IDO1 vaccine resulted in a clear increase in T cell infiltration and activation and the PD-L1 vaccine impacted the myeloid cell compartment. While further studies are needed to fully discern the relationship between IDO1+/PD-L1+ target populations within the TME and the impact of IDO1/PD-L1 targeted vaccination, our data support the use of a dual antigen approach to reduce the immunosuppression and enhance anti-tumor effect.