Across 28 reviewed Phase III gastric, gastroesophageal, and esophageal oncology trials, overall survival remained the dominant endpoint anchor but not the default standalone primary endpoint. OS appeared as a primary endpoint in 57.1% of trials, while another 32.1% positioned OS as a secondary endpoint behind PFS, DFS, EFS, diagnostic, surgical, or pharmacokinetic primary measures.
Overall survival was used as a primary endpoint in 57.1% of reviewed trials. This confirms OS remains the central confirmatory endpoint for many Phase III gastric cancer programs, but the remaining 42.9% used another endpoint as the primary measure.
OS remains the most important endpoint anchor, but Phase III gastric cancer submissions are no longer purely OS-led. A substantial share of trials now lead with PFS, DFS, EFS, imaging, surgical, or PK endpoints while retaining OS elsewhere in the endpoint hierarchy.
The dominant pattern was not a simple OS-versus-non-OS split. OS was a sole primary endpoint in 32.1% of trials and part of a co-primary or multi-primary design in 25.0%. A further 32.1% used OS as a secondary endpoint behind another primary measure.
The practical readout strategy is usually layered. Sponsors either keep OS as the primary proof point, combine it with faster event-driven endpoints, or move OS into secondary follow-up while another endpoint carries the primary statistical burden.
OS-primary use was visible in every authorization year, ranging from 50.0% to 71.4%. The 2026 cohort is too small to support a directional trend claim, but the broader pattern supports continued OS centrality rather than replacement by surrogate endpoints.
The available data do not justify a clean year-over-year trend narrative. The more reliable conclusion is structural: OS remains consistently present as either the primary endpoint or a major secondary endpoint across the cohort.
When OS was used as a primary endpoint, PFS was usually present somewhere in the design. 31.3% of OS-primary trials paired OS with PFS at the primary level, while 56.3% kept PFS as a secondary endpoint.
OS-primary trials still rely heavily on PFS to structure earlier efficacy interpretation. The practical design pattern is not OS instead of PFS, but OS plus PFS, often with RECIST-based assessment and central review language.
Among trials without OS as a primary endpoint, 66.7% still used another survival or event-driven endpoint as the primary measure, usually PFS, DFS, or EFS. The remaining 33.3% used diagnostic, operative, safety, or PK endpoints.
Non-OS primary designs are usually not abandoning survival logic. Most substitute a different time-to-event endpoint, while a smaller subset reflects diagnostic imaging, perioperative, pharmacokinetic, or operational objectives where OS is less suited to carry the primary endpoint.
For Phase III gastric, gastroesophageal, and esophageal oncology trials in Europe, OS remains the endpoint that most clearly signals confirmatory ambition. However, the endpoint strategy is increasingly layered: OS may be sole primary, co-primary with PFS, secondary behind PFS/DFS/EFS, or absent in diagnostic and perioperative studies where the trial question is not primarily survival benefit.
The competitive implication is straightforward: a new Phase III treatment program without OS either as primary or a major secondary endpoint will likely need a strong rationale. PFS, DFS, EFS, response, QoL, safety, biomarker, and surgical endpoints can add interpretive speed and differentiation, but OS still functions as the credibility anchor for late-stage gastric cancer development.