A Phase 3 interventional study of Zanidatamab and Tislelizumab in Gastric Neoplasms, Gastroesophageal Adenocarcinoma and Esophageal Adenocarcinoma, sponsored by Jazz Pharmaceuticals. Active, not recruiting at 227 sites in 33 countries. Open to participants aged 18 Years and older. Per ClinicalTrials.gov, last updated 2026-09-24.
Sponsored by Jazz Pharmaceuticals · Phase 3, Interventional, and Treatment
This study is being done to find out if zanidatamab, when given with chemotherapy plus or minus tislelizumab, is safe and works better than trastuzumab given with chemotherapy.
The patients in this study will have advanced human epidermal growth factor 2 (HER2)-positive stomach and esophageal cancers that are no longer treatable with surgery (unresectable) or chemoradiation, and/or have grown or spread to other parts of the body (metastatic).
Exclusion Criteria:
Trastuzumab (Herceptin®) plus physician's choice of capecitabine plus oxaliplatin (CAPOX) or 5-fluorouracil (5-FU) plus cisplatin (FP)
Drug: Trastuzumab · Drug: Capecitabine · Drug: Oxaliplatin · Drug: Cisplatin · Drug: 5-Fluorouracil
Zanidatamab plus physician's choice of CAPOX or FP
Drug: Zanidatamab · Drug: Capecitabine · Drug: Oxaliplatin · Drug: Cisplatin · Drug: 5-Fluorouracil
Zanidatamab and tislelizumab plus physician's choice of CAPOX or FP
Drug: Zanidatamab · Drug: Tislelizumab · Drug: Capecitabine · Drug: Oxaliplatin · Drug: Cisplatin · Drug: 5-Fluorouracil
Administered IV
Also known as: ZW25, JZP598, ZIIHERA®
Administered IV
Administered intravenously (IV)
Also known as: Herceptin®
Administered orally (PO bid)
Administered IV
Administered IV
Administered IV
Progression-free survival (PFS) by BICR
The time from randomization to the date of documented disease progression (per Response Evaluation Criteria in Solid Tumors \[RECIST\] version 1.1) as assessed by blinded independent central review (BICR) or death from any cause
Time frame: Up to 2.5 years
Overall survival
The time from randomization to death due to any cause
Time frame: Up to 3.5 years
Confirmed objective response rate (ORR) by BICR
Number of patients who achieved a best overall response of complete response (CR) or (PR) as determined per RECIST 1.1 as assessed by BICR
Time frame: Up to 2.5 years
Duration of response (DOR) by BICR
The time from the first objective response (CR or PR) per BICR to documented progressive disease per RECIST 1.1 as assessed by BICR or death from any cause
Time frame: Up to 2.5 years
PFS per Investigator assessment
The time from randomization to the date of documented disease progression (per RECIST 1.1) as assessed by Investigator or death from any cause
Time frame: Up to 2.5 years
Confirmed ORR per Investigator assessment
Number of patients who achieved a best overall response of CR or PR as determined per RECIST 1.1 as assessed by Investigator
Time frame: Up to 2.5 years
DOR per Investigator assessment
The time from the first objective response (CR or PR) per Investigator to documented progressive disease per RECIST 1.1 as assessed by Investigator or death from any cause
Time frame: Up to 2.5 years
Assessment of Contribution of Components based on Progression-free Survival (PFS) by BICR
The time from randomization to the date of documented disease progression (per Response Evaluation Criteria in Solid Tumors \[RECIST\] version 1.1) as assessed by blinded independent central review (BICR) or death from any cause
Time frame: Up to 2.5 years
Assessment of Contribution of Components based on Overall Survival
The time from randomization to death due to any cause
Time frame: Up to 3.5 years
Incidence of adverse events
Number of subjects who experienced adverse events or serious adverse events
Time frame: Up to 2 years
Incidence of clinical laboratory abnormalities
Number of patients who experienced a maximum severity of Grade 3 or higher post-baseline laboratory abnormality, including either hematology or chemistry. Grades are defined using National Cancer Institute's Common Terminology Criteria for Adverse Events (CTCAE), version 5.0
Time frame: Up to 2 years
Health-related quality of life (HRQoL) as assessed by the European Organisation for Research and Treatment of Cancer (EORTC) Quality of Life Questionnaire (core cancer questionnaire) C30 (QLQ-C30)
Changes from baseline in the EORTC QLQ-C30 scores
Time frame: Up to 2.5 years
HRQoL as assessed by the EORTC Quality of Life Questionnaire (oesophago-gastric module) OG25 (QLQ-OG25)
Changes from baseline in the EORTC QLQ-OG25 scores
Time frame: Up to 2.5 years
HRQoL as assessed by the EuroQol 5-dimensions 5-levels (EQ-5D-5L) questionnaire
Changes from baseline in the EORTC EQ-5D-5L questionnaire scores
Time frame: Up to 2.5 years
Serum concentration of zanidatamab and tislelizumab
Time frame: Up to 2 years
Incidence of anti-drug antibodies (ADAs)
Number of patients who develop ADAs
Time frame: Up to 2 years
Showing the first 100 of 227 sites across 33 countries.
Plan to share: Yes — In accordance with ICMJE requirements, Jazz Pharmaceuticals may provide qualified external researchers access to individual participant data (IPD) and clinical trial data that underlie the results of this trial upon request. Qualified researchers can submit a request on https://www.jazzpharma.com/science/clinical-trial-data-sharing/ as outlined. Jazz Pharmaceuticals reserves the right not to consider a request. For inquiries about Jazz's data sharing policy contact clinicaldatasharing@jazzpharma.com.
This study is active, not recruiting, as verified in Sep 2026. You cannot join it, but the record below documents what was studied.
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Jazz Pharmaceuticals