Canada-based Kainova Therapeutics has reported positive top line results from the Phase I EPRAD study of DT-9081, an oral EP4 receptor antagonist, in patients with advanced, recurrent, and metastatic solid tumours.

The trial was carried out at four clinical sites in Belgium and France, and results showed that all primary objectives were met.

It demonstrated a favourable safety profile for DT-9081. Pharmacodynamic and pharmacokinetic assessments indicated dose-proportional exposure and sustained EP4 receptor engagement at all tested doses.

No dose-limiting toxicities occurred at any dose level, confirming clinical tolerability and supporting the drug’s mechanism of action.

Early signals of anti-tumour activity were also observed. These findings further support the potential of DT-9081 to enhance responses to immune checkpoint inhibitors in various solid tumours.

DT-9081 is an oral small molecule designed to reverse Prostaglandin E2 (PGE2)-mediated immunosuppression in the tumour microenvironment by targeting the EP4 receptor.

Preclinical studies have demonstrated notable anti-tumour activity when used alone or alongside chemotherapy or immune checkpoint inhibitors across triple-negative breast cancer, sarcoma, and colorectal cancer.

DT-9081 targets the EP4 receptor with selective inhibition, aiming to re-establish an immunocompetent environment and facilitate immune system reactivation.

The clinical programme includes a biomarker strategy to enable precise monitoring of EP4 receptor engagement, optimise clinical positioning, de-risk development, and inform trial design.

Kainova's chief medical officer Dr Jean-Marie Cuillerot said: “The Phase I EPRAD study generated a clear and coherent dataset that precisely characterises DT-9081’s clinical profile.

“The high-quality clinical and translational data obtained in this study are essential for understanding how EP4 antagonism behaves in patients with advanced solid tumours in a clinical setting.”