Global prevalence of FGFR2b protein overexpression in advanced gastric cancer and gastroesophageal junction cancers: pooled analysis of two bemarituzumab phase III studies
2
Issued Date
2026-06-01
Resource Type
eISSN
20597029
Scopus ID
2-s2.0-105039833442
Journal Title
ESMO Open
Volume
11
Issue
6
Rights Holder(s)
SCOPUS
Bibliographic Citation
ESMO Open Vol.11 No.6 (2026)
Suggested Citation
Maron S.B., Xu R.H., Wainberg Z.A., Rha S.Y., Zhang Y., Pietrantonio F., Oliveira S.C.S., Li Y., Chen M.H., Korphaisarn K., Elimova E., Calderon C.A., Herpe F.V., Yong W.P., Dos Santos T.M., Tan M., Isse K., Yanes R.E., Shitara K. Global prevalence of FGFR2b protein overexpression in advanced gastric cancer and gastroesophageal junction cancers: pooled analysis of two bemarituzumab phase III studies. ESMO Open Vol.11 No.6 (2026). doi:10.1016/j.esmoop.2026.107698 Retrieved from: https://repository.li.mahidol.ac.th/handle/123456789/117017
Title
Global prevalence of FGFR2b protein overexpression in advanced gastric cancer and gastroesophageal junction cancers: pooled analysis of two bemarituzumab phase III studies
Author's Affiliation
KU Leuven
David Geffen School of Medicine at UCLA
Memorial Sloan Kettering Cancer Center
KU Leuven– University Hospital Leuven
Taipei Veterans General Hospital
Harbin Medical University
Princess Margaret Cancer Centre
Fondazione IRCCS Istituto Nazionale dei Tumori, Milan
Sun Yat-Sen University Cancer Center
Guangxi Medical University
Siriraj Hospital
National University Hospital
Amgen Incorporated
National Cancer Center Hospital East
Yonsei Cancer Hospital
Fundación Cardiovascular de Colombia
Liga Norte Riograndense Contra o Câncer
David Geffen School of Medicine at UCLA
Memorial Sloan Kettering Cancer Center
KU Leuven– University Hospital Leuven
Taipei Veterans General Hospital
Harbin Medical University
Princess Margaret Cancer Centre
Fondazione IRCCS Istituto Nazionale dei Tumori, Milan
Sun Yat-Sen University Cancer Center
Guangxi Medical University
Siriraj Hospital
National University Hospital
Amgen Incorporated
National Cancer Center Hospital East
Yonsei Cancer Hospital
Fundación Cardiovascular de Colombia
Liga Norte Riograndense Contra o Câncer
Corresponding Author(s)
Other Contributor(s)
Abstract
Background: Fibroblast growth factor receptor 2 isoform IIIb (FGFR2b) protein overexpression is an emerging biomarker and a potential therapeutic target in gastric and gastroesophageal junction cancers (G/GEJC). Limited data exist on the global prevalence of FGFR2b overexpression in advanced G/GEJC using a validated assay. We assessed the prevalence of FGFR2b protein overexpression in a pooled analysis of tumor samples collected as part of the prescreening process for two global phase III studies of bemarituzumab as first-line treatment for locally advanced or metastatic G/GEJC. Materials and methods: As of 20 February 2025, 7910 tumor samples from patients prescreened for enrollment in the FORTITUDE-101 (NCT05052801; n = 3752) and FORTITUDE-102 (NCT05111626; n = 4158) studies were centrally tested for FGFR2b protein overexpression by immunohistochemistry (IHC) and had evaluable results. FGFR2b overexpression was defined as both any percentage (>0%) of tumor cells (TCs) and ≥10% of TCs exhibiting moderate (2+) to strong (3+) membrane staining of FGFR2b. Prevalence was analyzed across defined patient and sample characteristics. Results: The estimated prevalence of FGFR2b any 2+/3+ was 36.5% [95% confidence interval (CI) 35.4-37.6; 2887/7910] and that of FGFR2b ≥10% 2+/3+ was 16.6% (95% CI 15.7-17.4; 1310/7910). Prevalence estimates from this pooled analysis and a separate analysis for FORTITUDE-102 [any 2+/3+: 35.8% (95% CI 34.3-37.2); FGFR2b ≥10% 2+/3+: 17.3% (95% CI 16.1-18.4)] were consistent with results previously reported for FORTITUDE-101 (Rha SY, Zhang Y, Elme A, et al. Prevalence of FGFR2b protein overexpression in advanced gastric cancers during prescreening for the phase III FORTITUDE-101 trial. JCO Precis Oncol. 2025;9:e2400710). FGFR2b prevalence was consistent across patient and sample characteristics [age, sex, collection method (biopsy versus resection), collection site, location of primary tumor, and geographic region]. Conclusion: This study represents the largest prevalence assessment of FGFR2b overexpression in G/GEJC using a validated IHC assay. The observed estimates of 36.5% (any 2+/3+) and 16.6% (FGFR2b ≥10% 2+/3+) suggest that FGFR2b is prevalent in a meaningful proportion of patients with advanced G/GEJC.