Press Release Details

Gosselies, Belgium - April 3, 2017 - iTeos Therapeutics SA, a biotechnology company developing novel cancer immunotherapies, will present preclinical data for its A_2A receptor antagonist, which inhibits the immune suppressive function of adenosine, at the American Association for Cancer Research (AACR) Annual Meeting. The poster titled, ‘A novel adenosine A_2A receptor antagonist optimized for high potency in adenosine-rich tumor microenvironment boosts anti-tumor immunity’ will be presented by Christophe Quéva, Chief Scientific Officer at iTeos Therapeutics, on April 3, 2017 at The Walter E. Washington Convention Center Washington, D.C.

iTeos Therapeutics has developed a novel and potent best-in-class A_2A blocker that has been specifically optimized for immuno-oncology indications to retain a high potency in the adenosine-rich environment found in tumors and to restore cytokine production even in the presence of high concentrations of adenosine. Furthermore, the data show that the compound is able to potently increase CD8 T cell cytotoxicity. The company showed how they first defined A_2A as the receptor required for mediating the effect of adenosine on immune cells within the tumor microenvironment and reported the characterization of a novel immuno-oncology-dedicated adenosine receptor 2A antagonist that functions in the high adenosine concentration found in tumors.

“These preclinical results show the potential of our compound to target the inhibition of the A_2A receptor in the challenging context of tumor-like adenosine concentrations. Such potency is not achieved by the competitive A_2A receptor antagonists initially designed for Parkinson’s disease,” said Christophe Quéva, Chief Scientific Officer of iTeos Therapeutics. “Our candidate has also been purposefully designed to be non-brain permeant in order to avoid potential CNS side effects. These findings hold strong promise for the development of new cancer therapeutic combinations with various oncology and immuno-oncology treatments.”

Michel Detheux, iTeos’ Chief Executive Officer added, “The progress of our adenosine A_2A antagonist program demonstrates how we can rapidly apply our expertise in medicinal chemistry, tumor immunology and translational medicine to advance candidates toward clinical development.”

About the A_2A Receptor and Oncology Applications

Extracellular adenosine is a signaling molecule known as an inhibitor of immune functions. High levels of adenosine and adenosine-producing enzymes are found in various tumor indications. Tumors use adenosine as an important process to evade immune attack and promote their survival. The adenosine A_2A receptor is the main adenosine receptor expressed on immune cell subsets including T-cells, NK cells and dendritic cells. Binding of adenosine to the A_2A receptor on immune cells blocks the activation and effector functions of anti-tumor immune cells and promotes a regulatory, immune-suppressive phenotype. A significant amount of scientific data underlines that targeting the adenosine-cancer axis through the A_2A receptor can promote anti-tumor immune responses and lead to tumor regression. Several clinical development programs in oncology are currently ongoing with compounds which were initially designed for Parkinson Disease.

About iTeos Therapeutics SA

Based in Gosselies, Belgium, iTeos, a spin-off from the Ludwig Cancer Research (LICR) and de Duve Institute (UCL), is focused on expanding the benefits of immunotherapy for cancer patients. The company is developing a proprietary pipeline targeting A_2A, immune checkpoints and non-inflamed tumors.  It has licensed its IDO1 program, now in Phase 1 development, to Pfizer. iTeos’ competitive edge is in the combination of expertise in drug discovery and translational tumor immunology. The company uses a unique platform to identify rational combinations of immunotherapies and novel targets. The company is supported in part by the Walloon Region of Belgium and the FEDER (European Fund for Economic and Regional Development). For more information please visit www.iteostherapeutics.com.

For further information, please contact:

Michel Detheux, CEO

iTeos Therapeutics

+32 71 919 933

michel.detheux@iteostherapeutics.com

Sarah McCabe

Stern Investor Relations, Inc.

+ 1 212 362-1200

sarah@sternir.com

Jonathan Birt, Mathew Neal, Hendrik Thys

Consilium Strategic Communications

+44 2 037 095 700

iteos@consilium-comms.com