A2A Receptor Antagonist

The ATP-adenosine pathway is recognized as a key pathway that modulates immune responses in pathological conditions. We designed EOS-850 to inhibit the ATP-adenosine pathway by specifically targeting A2AR, which is the primary adenosine receptor on immune cells with a high affinity for adenosine. We also chose to target A2AR because we believe it is a key mediator of immunosuppression in this pathway as opposed to targeting upstream enzymes that are involved in production of adenosine in tumors. A2AR is expressed across a number of solid tumors and hematological malignancies with high unmet medical need making it a target with broad clinical potential. As elevated levels of adenosine in the tumor microenvironment are known to be immunosuppressive, we also designed EOS-850 to remain potent at high adenosine concentrations and maintain continuous target coverage. With this profile, we believe that EOS-850 has the potential for enhanced antitumor activity as compared to other A2AR antagonists currently in clinical development. We are planning to assess EOS-850 in combination with pembrolizumab and with chemotherapy, initially evaluating safety and tolerability of the combination regimens before enrolling expansion cohorts in select indications.

Adenosine pathway