Non-Clinical Poster Data Support the Use of Dual Antigen Approach to Enhance Anti-Tumor Activity

NEW YORK, April  09, 2024  (GLOBE NEWSWIRE) -- IO Biotech (Nasdaq: IOBT), a clinical-stage biopharmaceutical company developing novel, immune-modulating therapeutic cancer vaccines based on its T-win platform, today 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.

"These data build on earlier studies that demonstrated the mechanism of IO102 and IO103," said Mai-Britt Zocca, Ph.D., President and CEO of IO Biotech. "We now clearly see that used together, IO102-IO103 create an environment in and around the tumor that allow for enhanced anti-tumor activity, at a much greater level than either could do on its own. With this additional data, we further understand the mechanistic rationale for the clinical effect observed in the Phase 1/2 study of IO102-IO103 that we hope to confirm in our ongoing Phase 3 pivotal study."

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.

The poster can be found on the "Posters & Publications" page of the IO Biotech website and on the AACR website. Details for the presentation are below:

Title: Immune modulatory cancer vaccines against IDO1 and PD-L1 trigger distinct pathways and cooperatively reduce tumor growth in preclinical models
Abstract Number: 4094
Time: Tuesday, April 9, 2024 9:00 AM - 12:30 PM PT
Presenter: Marion Chapellier, Ph.D., Senior Scientist R&D and translational research

About IO102-IO103

IO102-IO103 is an investigational, off-the-shelf therapeutic cancer vaccine designed to kill both tumor cells and immune-suppressive cells in the tumor microenvironment (TME) by stimulating activation and expansion of T cells against indoleamine 2,3-dioxygenase (IDO) and/or programmed death-ligand 1 (PD-L1) cells. The company is currently conducting a pivotal Phase 3 trial (IOB-013/KN-D18; NCT05155254) investigating IO102-IO103 in combination with pembrolizumab versus pembrolizumab alone in patients with advanced melanoma, a Phase 2 basket trial (IOB-022/KN-D38; NCT05077709) investigating IO102-IO103 in combination with pembrolizumab as first line treatment in patients with solid tumors, and a Phase 2 basket trial (IOB-032/PN-E40; NCT05280314) investigating IO102-IO103 in combination with pembrolizumab as neo-adjuvant/adjuvant treatment of patients with solid tumors.

The clinical trials are sponsored by IO Biotech and conducted in collaboration with Merck, and Merck is supplying pembrolizumab. IO Biotech maintains global commercial rights to IO102-IO103.

KEYTRUDA is a registered trademark of Merck Sharp & Dohme LLC, a subsidiary of Merck & Co., Inc., Rahway, NJ, USA.

About the IOB-013/KN-D18 Pivotal Phase 3 Clinical Trial

IOB-013/KN-D18 (Clinical Trials.gov: NCT05155254) is an open label, randomized Phase 3 clinical trial of IO102-IO103 in combination with pembrolizumab versus pembrolizumab alone in patients with previously untreated, unresectable or metastatic (advanced) melanoma, being conducted in collaboration with Merck. Patients have been enrolled from centers across the United States, Europe, Australia, Turkey, Israel and South Africa. The primary endpoint of the study is progression free survival. Biomarker analyses will also be conducted. IO Biotech is sponsoring the Phase 3 trial and Merck is supplying pembrolizumab. IO Biotech maintains global commercial rights to IO102-IO103.