IO Biotech Presents New Data at AACR 2025 Supporting Dual Mechanism and Immune Activation of Cancer Vaccines IO102-IO103 and IO170

Preclinical data further support the potential of dual-antigen and TGF-β-directed vaccines to reshape the tumor microenvironment and drive anti-tumor immunity

NEW YORK, April 25, 2025 (GLOBE NEWSWIRE) — IO Biotech (Nasdaq: IOBT), a clinical-stage biopharmaceutical company developing novel, immune-modulatory, off-the-shelf therapeutic cancer vaccines, today announced the presentation of new preclinical data for two vaccine candidates developed based on its T-win^® platform at the American Association for Cancer Research (AACR) Annual Meeting 2025 in Chicago, Illinois. One poster presentation provides further insights on the mode of action of IO102-IO103, the company’s lead investigational therapeutic cancer vaccine which targets cells expressing IDO1 and PD-L1, compared to conventional checkpoint inhibitors and a second shares promising updates for IO170, which targets Transforming Growth Factor beta (TGF-β).

“These data continue to strengthen our mechanistic rationale for using IO102-IO103 as a dual-antigen approach and for targeting key immunosuppressive drivers like TGF-β,” said Ayako Wakatsuki Pedersen, PhD, Senior Vice President of Translational Research at IO Biotech. “Together, these findings highlight how our vaccines act at multiple levels within the tumor microenvironment to drive more effective anti-tumor responses.”

Poster Highlights

• IO102-IO103, a dual-antigen vaccine targeting IDO1+ and PD-L1+ cells, generated strong T-cell responses and modulated the tumor microenvironment in two mouse models, where IDO1 and PD-L1 vaccine each contributed differently to control tumor growth. Gene expression profiling also showed that the vaccine triggered unique molecular changes not seen with PD-1 or PD-L1 inhibitors, indicating a potentially synergistic mechanism. (Abstract #2241)
• IO170, also developed using IO Biotech’s T-win^® platform, demonstrated significant tumor growth inhibition in breast and prostate cancer mouse models. The TGF- β-directed vaccine led to infiltration of vaccine-specific T cells with increased density of CD8+ T-cells in the tumor and reshaped the tumor microenvironment to favor immune activation. Spatial analysis in prostate tumors showed increased cytotoxic immune regions and reduced levels of suppressive cells like M2 macrophages. (Abstract #2257)

The posters can be found on the “Posters & Publications” page of the IO Biotech website and, for registered participants, on the AACR website.

About IO Biotech

IO Biotech is a clinical-stage biopharmaceutical company developing novel, immune-modulatory, off-the-shelf therapeutic cancer vaccines based on its T-win^® platform. The T-win platform is based on a novel approach to cancer vaccines designed to activate T cells to target both tumor cells and the immune-suppressive cells in the tumor microenvironment. IO Biotech is advancing its lead investigational cancer vaccine candidate, Cylembio^® (imsapepimut and etimupepimut, adjuvanted) also known as IO102-IO103 in clinical trials, and additional pipeline candidates through preclinical development. Based on positive Phase 1/2 first line metastatic melanoma data, IO102-IO103, in combination with Merck’s anti-PD-1 therapy, KEYTRUDA^® (pembrolizumab), has been granted a Breakthrough Therapy Designation for the treatment of advanced melanoma by the US Food and Drug Administration. IO Biotech is headquartered in Copenhagen, Denmark and has US headquarters in New York, New York.

For further information, please visit www.iobiotech.com. Follow us on our social media channels on LinkedIn and X (@IOBiotech).

Cylembio^® is a registered trademark of IO Biotech ApS, a subsidiary of IO Biotech.

Forward-Looking Statement

This press release contains forward-looking statements within the meaning of Section 27A of the Securities Act of 1933, as amended, and Section 21E of the Securities Exchange Act of 1934, as amended. Forward-looking statements, including regarding the timing or outcome of primary analysis of the company’s Phase 3 trial, other current or future clinical trials, their progress, enrollment or results, or the company’s financial position or cash runway, are based on IO Biotech’s current assumptions and expectations of future events and trends, which affect or may affect its business, strategy, operations or financial performance, and actual results and other events may differ materially from those expressed or implied in such statements due to numerous risks and uncertainties. Forward-looking statements are inherently subject to risks and uncertainties, some of which cannot be predicted or quantified. Because forward-looking statements are inherently subject to risks and uncertainties, you should not rely on these forward-looking statements as predictions of future events. These forward-looking statements speak only as of the date hereof and should not be unduly relied upon. Except to the extent required by law, IO Biotech undertakes no obligation to update these statements, whether as a result of any new information, future developments or otherwise.

Contact:

Investors
Maryann Cimino, Director of Investor Relations
IO Biotech, Inc.
617-710-7305
mci@iobiotech.com

Media
Julie Funesti
Edelman
917-498-1967
julie.funesti@edelman.com