A Prospective Observational Study on the Dynamics of Claudin18.2, PD-L1, and HER2 Expression Following First-Line Treatment in Patients with Advanced Gastric or Gastroesophageal Junction Adenocarcinoma.

A Prospective Observational Study on the Dynamics of Claudin18.2, PD-L1, and HER2 Expression Following First-Line Treatment in Patients with Advanced Gastric or Gastroesophageal Junction Adenocarcinoma. - A Prospective Observational Study on the Dynamics of Claudin18.2, PD-L1, and HER2 Expression Following First-Line Treatment in Patients with Advanced Gastric or Gastroesophageal Junction Adenocarcinoma.

Status

Recruiting

Phases

Unknown

Study type

Observational

Source

JPRN

Registry ID

JPRN-UMIN000059987

Enrollment

Registered

2025-12-05

Start date

2025-12-05

Completion date

Unknown

Last updated

2026-06-29

For informational purposes only — not medical advice. Sourced from public registries and may not reflect the latest updates. Terms

Conditions

To investigate the potential usefulness of zolbetuximab, primarily as a second-line or later treatment, by evaluating changes in key biomarkers, including Claudin 18.2 (CLDN18.2), before and after first-line treatment for unresectable gastric cancer and gastroesophageal junction cancer.

Interventions

None listed

Eligibility

Sex/Gender

All

Inclusion criteria

Inclusion criteria: (1)Unresectable gastric cancer or gastroesophageal junction cancer (2)Histologically confirmed adenocarcinoma (3)CLDN18.2, PD-L1 CPS (22C3), and HER2 status are known before the start of first-line treatment (4)There is a Primary tumor (5)Patients currently undergoing any of the following first-line treatments, or whose first-line treatments have been discontinued due to reactivity, intolerance, or patient preference: A.Zolbetuximab-containing chemotherapy* for HER2-negative and CLDN18.2-positive patients B.Anti-PD-1 antibody-containing chemotherapy* for HER2-negative and CLDN18.2-negative patients C.Trastuzumab-containing chemotherapy* for HER2-positive patients (including chemotherapy + trastuzumab + pembrolizumab) *Chemotherapy: Fluoropyrimidine preparations + platinum (6)Patients scheduled for upper gastrointestinal endoscopy and biopsy for the purpose of primary tumor evaluation, etc., upon discontinuation of first-line treatment

Exclusion criteria

Exclusion criteria: (1)Cases in which the treatment period (start date to stop date) of first-line treatment is less than 6 weeks (2)Cases in which second-line treatment has already begun (3)Cases in which the subject did not consent to the use of his/her specimen for research purposes. (4)Cases in which the principal investigator determines that participation in this study is inappropriate.

Design outcomes

Primary

Measure	Time frame
Changes in CLDN18.2 expression before and after first-line treatment	—

Countries

Japan

Contacts

Public ContactManami Onoue

St. Marianna University School of Medicine Department of Clinical Oncology

manami1o@marianna-u.ac.jp0449778111

Outcome results