Our Science


Pushing the boundaries of what’s possible.
IO Biotech is pioneering the development of novel immune-modulatory, off-the-shelf therapeutic cancer vaccines. Our T-win® vaccine candidates are designed to kill both tumor cells and immune-suppressive cells in the tumor microenvironment (TME). Enrollment in the trial of our lead asset Cylembio® (imsapepimut and etimupepimut, adjuvanted), also known as IO102-IO103, in combination with the anti-PD-1 monoclonal antibody pembrolizumab versus pembrolizumab alone as first-line therapy in patients with unresectable or metastatic (advanced) melanoma was completed rapidly by December 2023. The company reported topline results from this trial in the third quarter of 2025. Read More
The T-win® cancer vaccine platform is designed to stimulate T cells against tumor cells and the most important immune-suppressive cells – Tregs and tumor-associated macrophages (TAMs) – in the TME, turning it into an anti-tumor, pro-inflammatory environment. The T-win® platform’s novel and highly differentiated mechanism of action has demonstrated clinical activity without additional significant systemic toxicity when administered in combination with an approved anti-PD-1 therapy.
IO Biotech aims to improve outcomes with the development of immune-modulatory, off-the-shelf therapeutic cancer vaccines with novel dual mechanisms of action to optimize treatment response, without adding toxicity, in both advanced and earlier stages of cancer.
Cylembio™ (imsapepimut and etimupepimut, adjuvanted)
Our lead investigational immune-modulatory, off-the-shelf therapeutic cancer vaccine candidate Cylembio combines our two wholly owned T-win® cancer vaccines, IO102 targeting IDO1 and IO103 targeting PD-L1, that are designed to kill both tumor cells and immune-suppressive cells in the TME, by stimulating activation and expansion of T cells against IDO1+ and/or PD-L1+ cells, respectively. IDO1 and PD-L1 are overexpressed by immune-suppressive cells in many solid tumors. By combining IO102 and IO103, our lead product candidate is intended to modulate the TME, potentiating anti-tumor activity via unleashing the tumor killing by effector T cells.
IO112
IO112 is our wholly owned, novel T-win® immune-modulatory, therapeutic cancer vaccine candidate that is designed to activate and expand T cells specific for arginase-1 positive/-expressing cells. Arginase-1 is highly expressed in difficult-to-treat tumors – including breast, colorectal, pancreatic, prostate and ovarian cancers – that are associated with high levels of immune-suppressive cells in the TME. By directing T cells against tumor cells and immune-suppressive cells in the TME expressing arginase-1, IO112 could offer a new therapeutic option to patients with these tumor types.
IO170
IO170 is our wholly owned, novel T-win® immune-modulatory, therapeutic cancer vaccine candidate that is designed to target growth factor beta 1 (TGFβ1) expressing cells in the TME to modulate the pathway and drive therapeutic benefit. We are developing and characterizing TGFβ1-selective peptide vaccines capable of inducing strong immune responses. Preliminary evidence in mouse models showed that treatment with a TGFβ1 vaccine drives T cell infiltration in the TME and might promote in vivo targeted cell killing. We are currently conducting further experimental work to elucidate the cellular and molecular mechanisms of a TGFβ1 vaccine to support further development of a TGFβ1 vaccine (IO170) to modulate the TME for therapeutic benefit in a wide range of cancer indications.