First patient dosed in study of novel EP4 antagonist for advanced solid tumoursNxera Pharma and Cancer Research UK have announced the first patient has been dosed in a phase 2a trial of HTL0039732, an investigational oral EP4 antagonist being developed to treat advanced solid tumours in combination with immunotherapy. The trial follows successful completion of phase 1, which identified a safe and well-tolerated dose of HTL0039732 with checkpoint inhibitor atezolizumab. HTL0039732 blocks signalling through the prostaglandin E2 receptor EP4, which helps cancer cells evade immune detection. The trial is sponsored and managed by Cancer Research UK’s Centre for Drug Development. The phase 2a study includes four patient cohorts: microsatellite stable colorectal cancer, gastric or gastroesophageal junction adenocarcinoma, clear cell renal cell carcinoma, and metastatic castration-resistant prostate cancer.