OncoMatch/Clinical Trials/NCT07673887
A Study of ASP2138 Together With Chemotherapy and Pembrolizumab in Adults With Gastric Cancer
Is NCT07673887 recruiting? Yes, currently enrolling (Sep 2026). This Phase 3 trial studies multiple treatments for gastric adenocarcinoma.
Treatment: ASP2138 · Pembrolizumab · Oxaliplatin · Capecitabine · Folinic acid · 5-FU — Claudin 18.2 or CLDN18.2 is a protein found on cells in the digestive system. It is also found in some tumors. Researchers are looking at ways to attack CLDN18.2 to help control tumors. ASP2138 is thought to bind to CLDN18.2 and a type of immune cell called a T cell. This "tells" the immune system to attack the tumor. ASP2138 is a potential treatment for people with gastric cancer (also known as stomach cancer) or gastroesophageal junction cancer (GEJ cancer). GEJ is where the tube that carries food (esophagus) joins the stomach. This study is for people with gastric or GEJ cancer that has spread nearby (locally advanced) and is not removable by surgery (unresectable), or has spread to other parts of the body (metastatic). It is for those whose cancer is human epidermal growth factor receptor 2 (HER2)-negative and CLDN18.2-positive. HER2-negative means the cancer does not have extra HER2 protein, so medicines that target HER2 do not work and are therefore not used. CLDN18.2-positive means people have a certain amount of CLDN18.2 proteins on their cancer cells. In this study, researchers want to learn if ASP2138 given together with standard treatments (chemotherapy and pembrolizumab) help people with HER2-negative and CLDN18.2-positive gastric or GEJ cancer. The main aim is to learn how long people who are given ASP2138 with chemotherapy and pembrolizumab live without their cancer getting worse, compared with placebo given with chemotherapy with or without pembrolizumab, and if they live for longer. Placebo looks like the study treatment but does not have any medicine in it. The main aim of this study is to check how well ASP2138 works when given together with chemotherapy and pembrolizumab compared with placebo plus chemotherapy with or without pembrolizumab. People aged 18 years or older with locally advanced unresectable or metastatic gastric or GEJ cancer can take part. Their tumor should be HER2-negative and CLDN18.2-positive. The study doctors will check people for any health conditions that can exclude them from taking part, interfere with the study procedures, or pose an unacceptable risk. This is a double-blind study. That means the people and the study doctors will not know who will receive which treatment. People will be assigned to one of 2 treatment groups by chance: Group A: People will receive ASP2138 along with chemotherapy and pembrolizumab. Group B: People will receive placebo along with chemotherapy, with or without pembrolizumab. People will keep receiving treatment until their cancer gets worse, they have medical problems that require stopping treatment, or a study rule says they must stop. There will be regular safety checks. People will continue to have scans of their tumor until their cancer becomes worse.
Check if I qualifyExtracted eligibility criteria
Treatments studied
Immunotherapy
Chemotherapy
Other
Cancer type
Gastric Cancer
Esophageal Carcinoma
Biomarker criteria
Required: HER2 (ERBB2) wild-type
HER2-negative (HER2 immunohistochemistry (IHC) score 0+/1+ or HER2 IHC score 2+/in situ hybridization (ISH) negative)
Required: CLDN18 expression (positive)
CLDN18.2-positive tumor as determined by central testing
Required: PD-L1 (CD274) any tested (testing required; no eligibility threshold specified)
valid programmed death-ligand 1 (PD-L1) result as determined by central testing of a tumor sample
Allowed: MSI high
Participant with known microsatellite instability-high ... may enroll as long as their tumor expresses PD-L1 combined positive score (CPS) >= 1 as determined by central IHC testing
Allowed: MLH1 loss
Participant with known ... mismatch repair deficient status may enroll as long as their tumor expresses PD-L1 combined positive score (CPS) >= 1 as determined by central IHC testing
Allowed: MSH2 loss
Participant with known ... mismatch repair deficient status may enroll as long as their tumor expresses PD-L1 combined positive score (CPS) >= 1 as determined by central IHC testing
Allowed: MSH6 loss
Participant with known ... mismatch repair deficient status may enroll as long as their tumor expresses PD-L1 combined positive score (CPS) >= 1 as determined by central IHC testing
Allowed: PMS2 loss
Participant with known ... mismatch repair deficient status may enroll as long as their tumor expresses PD-L1 combined positive score (CPS) >= 1 as determined by central IHC testing
Performance status
ECOG 0–1(Restricted strenuous activity)
Prior therapy
Cannot have received: systemic chemotherapy and/or immunotherapy for locally advanced unresectable or metastatic gastric or GEJ adenocarcinoma
Exception: a maximum of 1 cycle of mFOLFOX6 or CAPOX with or without immunotherapy (for those participants with CPS >= 1) is allowed to be administered prior to randomization (no dose modifications allowed for the lead-in treatment); prior neoadjuvant or adjuvant chemotherapy, immunotherapy, or other systemic anticancer therapies allowed if completed at least 6 months prior to randomization and disease progression occurs at least 6 months after the last dose
received prior systemic chemotherapy and/or immunotherapy for locally advanced unresectable or metastatic gastric or GEJ adenocarcinoma
Cannot have received: anti-PD-1, anti-PD-L1 or anti-PD-L2 agent, or agent directed to another stimulatory or coinhibitory T-cell receptor (e.g., CTLA-4, OX-40, CD137)
Exception: unless received in the perioperative setting
prior therapy with an anti-PD-1, anti-PD-L1 or anti-PD-L2 agent, or with an agent directed to another stimulatory or coinhibitory T-cell receptor (e.g., CTLA-4, OX-40, CD137) unless received in the perioperative setting
Lab requirements
Blood counts
hemoglobin >= 9 g/dL (posttransfusion, 24 hours or later following transfusion)
Kidney function
Liver function
Cardiac function
QTc interval > 450 msec for male participants; QTc interval > 470 msec for female participants; exclusion of NYHA Class III/IV heart failure, recent MI, unstable angina, etc.
must meet all of the criteria based on the centrally or locally analyzed laboratory tests collected within 14 days prior to randomization ... hemoglobin >= 9 g/dL ... exclusion criteria: significant cardiovascular disease, QTc interval > 450 msec (male), > 470 msec (female), etc.
Structured fields extracted by AI. May contain errors — verify against the official protocol.
Frequently asked questions
Is NCT07673887 currently recruiting?
Yes, this trial is currently recruiting patients.
Are there prior therapy exclusions?
Yes. Prior systemic chemotherapy and/or immunotherapy for locally advanced unresectable or metastatic gastric or GEJ adenocarcinoma, anti-PD-1, anti-PD-L1 or anti-PD-L2 agent, or agent directed to another stimulatory or coinhibitory T-cell receptor (e.g., CTLA-4, OX-40, CD137) disqualifies patients from enrollment.
Does this trial require ERBB2?
Yes, ERBB2 wild-type is a required biomarker for enrollment.
Does this trial require CLDN18?
Yes, CLDN18 expression is a required biomarker for enrollment.
Does this trial require CD274?
Yes, CD274 any tested is a required biomarker for enrollment.
Could you qualify for this trial?
Enter your biomarker results to see how this trial's eligibility criteria match your specific cancer profile.
Check if I qualify