CLDN18.2 expression prevalence of 33.99% in patients with gastric and gastroesophageal junction adenocarcinomaNew data shows how many stomach cancer patients have target protein

This meta-analysis evaluated the prevalence of CLDN18.2 expression in a large cohort of patients diagnosed with gastric adenocarcinoma and gastroesophageal junction adenocarcinoma. The study included a total of 12,173 patients to determine the frequency of this specific biomarker, which is relevant for identifying candidates for targeted therapies such as zolbetuximab. The analysis focused on the presence of CLDN18.2 expression at the 75% moderate-to-strong membranous staining threshold.

The primary outcome of the analysis was the pooled prevalence of CLDN18.2 positivity. The study reported a pooled prevalence of 33.99% (95% CI: 30.13%-38.07%; 95% prediction interval: approximately 18%-55%). This finding provides a quantitative baseline for the prevalence of the target in the specified patient population. The high between-study heterogeneity (I2 = 92.4%) indicates significant variability across the included studies, which may reflect differences in clinical settings or testing methodologies.

Several subgroup analyses were conducted to refine the understanding of CLDN18.2 expression. When analyzed by the 43-14 A antibody clone, the prevalence was 32.79% (95% CI: 28.86%-36.97%; p = 0.281). In contrast, when using other antibody clones, the prevalence was higher at 41.74% (95% CI: 26.76%-58.42%). Geographic analyses also provided nuanced data: non-Asian populations showed a prevalence of 37.85% (95% CI: 31.59%-44.54%; p = 0.169), while Asian populations showed a prevalence of 32.10% (95% CI: 27.28%-37.34%).

Regarding safety and tolerability, the data were not reported in the meta-analysis. Because the study focused on the prevalence of a biomarker rather than the administration of a therapeutic agent, adverse event rates, serious adverse events, and discontinuation rates were not captured. The study design was focused on diagnostic and prevalence metrics rather than clinical trial outcomes.

These results provide a foundational understanding of biomarker distribution in gastric and gastroesophageal junction cancers. However, the study notes that the pooled estimate of 33.99% should not be interpreted directly as the proportion of patients eligible for zolbetuximab. This is due to the heterogeneous disease settings and the fact that the population was predominantly not selected for HER2 status, which may influence the clinical applicability of the data in specific treatment protocols.

Methodological limitations include the high between-study heterogeneity (I2 = 92.4%) and the heterogeneous disease settings across the included studies. Additionally, the population was predominantly not selected for HER2 status, which may impact the generalizability of the findings to specific subsets of patients. These factors necessitate a cautious interpretation of the data when making clinical decisions regarding patient selection for targeted therapies.

Clinically, these results provide an evidence base for understanding CLDN18.2 prevalence and the necessity of biomarker testing. While the data confirm the presence of the target in a significant portion of the population, the heterogeneity means that local clinical settings may vary significantly. Questions remain regarding how these prevalence rates translate to specific treatment responses in diverse populations and how different testing methodologies impact the consistency of results across different regions.