Ono Pharmaceutical reported that ONO-4578, an EP4 receptor antagonist developed with Bristol Myers Squibb outside certain territories, hit the progression‑free survival (PFS) primary endpoint in a randomized Phase 2 trial for HER2‑negative unresectable or recurrent gastric and gastroesophageal junction cancer. The compound was tested in combination with BMS’ PD‑1 inhibitor nivolumab (Opdivo) plus chemotherapy across sites in Japan, South Korea and Taiwan. Ono did not release numeric data in its announcement but said the trial met statistical significance and that full results will be presented at a forthcoming scientific meeting. The readout validates EP4 as an immunomodulatory axis in the tumor microenvironment and keeps ONO‑4578 on a development path that includes global colorectal studies. The result reinforces interest in combination immuno‑oncology strategies that target immunosuppressive prostaglandin pathways.