Perioperative Chemotherapy With Low-Dose Radiotherapy and Tislelizumab for Locally Advanced Gastric or Gastroesophageal Junction Adenocarcinoma

A Phase II Multicenter Randomized Controlled Trial of Perioperative Chemotherapy Combined With Low-Dose Radiotherapy and Tislelizumab Versus Chemotherapy Alone in Patients With Locally Advanced Gastric or Gastroesophageal Junction Adenocarcinoma

This study is a prospective, multicenter, randomized, phase II clinical trial enrolling patients with resectable locally advanced gastric or gastroesophageal junction adenocarcinoma. The study aims to compare the efficacy and safety of perioperative chemotherapy combined with low-dose radiotherapy and tislelizumab versus perioperative chemotherapy alone in this patient population.

Study Overview

• Status: Not yet recruiting
• Conditions: Gastric or Gastroesophageal Junction Adenocarcinoma
• Intervention / Treatment: Drug: Low Dose Radiotherapy Combined with Tislelizumab and Chemotherapy; Device: low-dose radiotherapy; Drug: Chemotherapeutic Agent

• Study Type: Interventional
• Enrollment (Estimated): 114
• Phase: Phase 2

Participation Criteria

Eligibility Criteria

• Ages Eligible for Study: Adult; Older Adult
• Accepts Healthy Volunteers: No

Description

Inclusion Criteria:

1.Voluntary participation with written informed consent obtained; 2. Histologically confirmed gastric or gastroesophageal junction adenocarcinoma (Siewert type II/III) by endoscopic biopsy (pathology from outside institutions must be reviewed by the study center); 3. Staged as cT1-2N1-3M0 or cT3-4aN0-3M0 according to the AJCC 8th edition, based on endoscopy and imaging (CT, MRI, or PET-CT); 4. Age ≥20 and ≤80 years, male or female; ECOG performance status of 0-1; 5. Presence of measurable and/or non-measurable disease per RECIST v1.1; 6.No prior systemic antitumor therapy, including chemotherapy, radiotherapy, targeted therapy, immunotherapy, biologic therapy, local therapy, or investigational agents; Adequate organ function (no blood products or growth factors within 2 weeks prior to screening); 7. Women of childbearing potential must have a negative pregnancy test within 72 hours prior to first dosing and agree to use effective contraception during the study and for 5 months after the last dose; men with partners of childbearing potential must use effective contraception during the study and for 7 months after the last dose.

Exclusion Criteria:

1. History of surgery for gastric or gastroesophageal junction tumors;
2. Prior history of fistula formation caused by invasion of the primary tumor; 3.High risk of gastrointestinal bleeding or perforation;

4.Poor nutritional status, defined as BMI <18.5 kg/m² or PG-SGA score ≥9; 5. Major surgery or severe trauma within 4 weeks prior to first study drug administration; Uncontrolled pleural effusion, pericardial effusion, or ascites requiring repeated drainage; 6. Prior or ongoing treatment with anti-PD-1/PD-L1 antibodies, chemotherapy, radiotherapy, or targeted therapy; 7. Use of any investigational drug within 4 weeks prior to first study drug administration; Requirement for systemic corticosteroids; 8. Prior receipt of antitumor vaccines or live vaccines within 4 weeks before first study drug administration; 9. Active autoimmune disease or history of autoimmune disease; 10.History of immunodeficiency, including HIV infection, other acquired or congenital immunodeficiency, solid organ transplantation, or allogeneic bone marrow transplantation; 11.Any condition requiring systemic corticosteroid or immunosuppressive therapy within 14 days prior to treatment, except for minimal systemic absorption routes or short-term (≤7 days) prophylactic use; 12.Uncontrolled clinically significant cardiac disease, including NYHA class II or higher heart failure, unstable angina, myocardial infarction within 1 year, or clinically significant arrhythmias requiring intervention; 13.Severe infection (CTCAE grade >2) within 4 weeks prior to treatment, including infections requiring hospitalization; evidence of active pulmonary infection at baseline imaging or infections requiring antibiotics within 2 weeks prior to enrollment (prophylactic antibiotics excluded); 14.History of interstitial lung disease, noninfectious pneumonitis, pulmonary fibrosis, or other uncontrolled acute pulmonary disease; 15.Active tuberculosis, history of active tuberculosis within 1 year prior to enrollment, or inadequately treated tuberculosis more than 1 year prior; 16.Active hepatitis B (HBV DNA ≥2,000 IU/mL) or hepatitis C infection (HCV antibody positive with detectable HCV RNA); 17.Any condition requiring systemic corticosteroid or immunosuppressive therapy within 14 days prior to treatment, except for minimal systemic absorption routes or short-term (≤7 days) prophylactic use; 18.Uncontrolled clinically significant cardiac disease, including NYHA class II or higher heart failure, unstable angina, myocardial infarction within 1 year, or clinically significant arrhythmias requiring intervention; 19.Severe infection (CTCAE grade >2) within 4 weeks prior to treatment; History of interstitial lung disease, noninfectious pneumonitis, pulmonary fibrosis, or other uncontrolled acute pulmonary disease; 20.Active tuberculosis, history of active tuberculosis within 1 year prior to enrollment, or inadequately treated tuberculosis more than 1 year prior; 21.Active hepatitis B (HBV DNA ≥2,000 IU/mL) or hepatitis C infection (HCV antibody positive with detectable HCV RNA); 22.Grade >1 abnormalities in serum sodium, potassium, or calcium within 2 weeks prior to enrollment that cannot be corrected with treatment.

Study Plan

How is the study designed?

Design Details

• Primary Purpose: Treatment
• Allocation: Randomized
• Interventional Model: Parallel Assignment
• Masking: None (Open Label)

Number of Arms

2

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Active Comparator: Chemotherapy	Drug: Chemotherapeutic Agent; Chemotherapy: Oxaliplatin 130 mg/m² on days 1 and 22 plus capecitabine 1000 mg/m² twice daily on days 1-14, for a total of 3 cycles.
Experimental: Chemotherapy combined with Tislelizumab	Drug: Low Dose Radiotherapy Combined with Tislelizumab and Chemotherapy; Chemotherapy: Oxaliplatin 130 mg/m² on days 1 and 22 plus capecitabine 1000 mg/m² twice daily on days 1-14, for a total of 3 cycles.Tislelizumab: 200 mg administered concurrently with chemotherapy on days 1 and 22 via intravenous infusion, for a total of 3 cycles. Low Dose Radiotherapy: Initiated within one week after the start of chemotherapy; total dose (DT): 30 Gy.; Device: low-dose radiotherapy; Radiotherapy: Initiated within one week after the start of chemotherapy; total dose (DT): 30 Gy.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pathological Complete Response (pCR) Rate (ITT Population)	The pathological complete response (pCR) rate is defined as the proportion of patients in the intention-to-treat (ITT) population who achieve pathological complete response after neoadjuvant treatment. Pathological complete response is defined as the absence of residual viable tumor cells in the resected primary tumor and all sampled regional lymph nodes (ypT0N0), as determined by histopathological examination of the surgical specimens according to standardized pathological assessment criteria.	At the time of surgery following completion of neoadjuvant therapy, based on pathological evaluation of the resected surgical specimen.

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Pathological Complete Response (pCR) Rate (Surgical Population)	The pathological complete response (pCR) rate in the surgical population is defined as the proportion of patients who undergo surgical resection and achieve pathological complete response after neoadjuvant treatment. Pathological complete response is defined as the absence of residual viable tumor cells in the resected primary tumor and all sampled regional lymph nodes (ypT0N0), as determined by histopathological examination of the surgical specimens according to standardized pathological assessment criteria.	At the time of surgery following completion of neoadjuvant therapy, based on pathological evaluation of the resected surgical specimen.
R0 Resection Rate	The R0 resection rate is defined as the proportion of patients who undergo surgical resection and achieve microscopically margin-negative resection (R0). R0 resection is defined as no residual tumor at the resection margins on histopathological examination of the surgical specimen, as assessed according to standard pathological criteria.	At the time of surgery, based on pathological evaluation of the resected surgical specimen.
Event-Free Survival (EFS)	Event-free survival (EFS) is defined as the time from randomization (or from treatment initiation in single-arm studies) to the first occurrence of any of the following events: disease progression precluding surgical resection, local or distant recurrence after surgery, or death from any cause. Patients who do not experience any of these events at the time of analysis will be censored at the date of the last disease assessment.	From the date of randomization until the occurrence of disease progression, recurrence, death, or end of follow-up, whichever occurs first, assessed up 60 months.
Overall Survival (OS)	Overall survival (OS) is defined as the time from randomization to death from any cause. Patients who are alive at the time of analysis will be censored at the date of last follow-up.	From the date of randomization until death from any cause or end of follow-up, whichever occurs first, assessed up to 60 months.

Collaborators and Investigators

• Sponsor: Jiangsu Cancer Institute & Hospital

Study record dates

Study Major Dates

• Study Start (Estimated): February 26, 2026
• Primary Completion (Estimated): February 20, 2029
• Study Completion (Estimated): February 20, 2031

Study Registration Dates

• First Submitted: February 6, 2026
• First Submitted That Met QC Criteria: February 12, 2026
• First Posted (Actual): February 13, 2026

Study Record Updates

• Last Update Posted (Actual): February 13, 2026
• Last Update Submitted That Met QC Criteria: February 12, 2026
• Last Verified: February 1, 2026

More Information

Terms related to this study

• Additional Relevant MeSH Terms: Therapeutics; Pharmacologic Actions; Chemical Actions and Uses; Therapeutic Uses; Antineoplastic Agents; Radiotherapy; Drug Therapy; tislelizumab
• Other Study ID Numbers: GAS-Jiangsu04

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No
• product manufactured in and exported from the U.S.: No