Adaptive Adjuvant Therapy After Neoadjuvant Therapy and Gastrectomy for Gastric or Gastroesophageal Junction Adenocarcinoma

Efficacy and Safety of Postoperative Adaptive Adjuvant Therapy After Neoadjuvant Therapy and Radical Gastrectomy for Gastric or Gastroesophageal Junction Adenocarcinoma: A Prospective, Multicenter, Open-Label Clinical Trial

The goal of this clinical trial is to evaluate postoperative adaptive adjuvant therapy in patients with gastric or gastroesophageal junction adenocarcinoma after neoadjuvant chemotherapy plus immunotherapy and radical gastrectomy.The main questions it aims to answer are:

1. In patients with poor pathological response, does switching to a alternative postoperative treatment regimen improve survival?
2. In patients with complete pathological response, can observation without routine postoperative treatment maintain favorable survival outcomes? Participants will be assigned to different cohorts according to their pathological response after surgery and will be followed regularly for recurrence, survival, and treatment-related side effects.

Study Overview

• Status: Not yet recruiting
• Conditions: Gastric Adenocarcinoma; Gastroesophageal Junction Adenocarcinoma
• Intervention / Treatment: Drug: Alternative Postoperative Treatment Regimen; Drug: Original Treatment Regimen; Other: Postoperative Observation

Detailed Description

This prospective clinical trial will enroll patients with gastric or gastroesophageal junction adenocarcinoma who have received neoadjuvant chemotherapy plus immunotherapy followed by radical gastrectomy. Participants will be assigned to predefined cohorts according to postoperative pathological response and pathological stage.

Patients with poor pathological response, defined as TRG 3 and ypT3-4N2-3M0 disease, will be evaluated to determine whether switching to a alternative postoperative treatment regimen improves survival and remains safe compared with continuing the original treatment regimen. For patients with complete pathological response, defined as TRG 0 and ypT0N0M0 disease, will be evaluated to determine whether observation without routine postoperative treatment maintain favorable survival outcomes.

The study aims to assess whether postoperative treatment can be adapted according to pathological response after neoadjuvant therapy, rather than applying the same postoperative treatment strategy to all patients. The results may help develop more individualized postoperative management strategies for patients at very high or very low risk of recurrence after neoadjuvant therapy and radical surgery.

• Study Type: Interventional
• Enrollment (Estimated): 405
• Phase: Phase 2; Phase 3

Contacts and Locations

• Study Contact: Name: Liying Zhao, M.D., Ph.D; Phone Number: 13430396746; Email: zlyblue11@163.com

Study Locations

• China
  • Guangdong
    • Guangzhou, Guangdong, China
      • Nanfang Hospital, Southern Medical University
      • Contact: Liying Zhao, M.D., Ph.D; Phone Number: 13430396746; Email: zlyblue11@163.com

Participation Criteria

Eligibility Criteria

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

Description

Key Inclusion Criteria:

1. Voluntarily signed written informed consent.
2. Aged 18 to 75 years, inclusive, regardless of sex.
3. Underwent radical gastrectomy with D2 or more extended lymphadenectomy and achieved R0 resection. Surgical approaches may include open or laparoscopic surgery.
4. Histopathologically confirmed gastric or gastroesophageal junction adenocarcinoma.
5. Received preoperative neoadjuvant immunotherapy combined with chemotherapy, including oxaliplatin plus fluoropyrimidine-based chemotherapy. Immunotherapy may include anti-PD-1 monoclonal antibodies, anti-PD-L1 monoclonal antibodies, PD-1/CTLA-4 bispecific antibodies, and other immune checkpoint inhibitors.

6. Eligible for one of the following predefined cohorts:

   • Cohort 1: TRG grade 3 and postoperative pathological stage ypT3-4N2-3M0.
   • Cohort 2: TRG grade 0 and postoperative pathological stage ypT0N0M0.
7. ECOG performance status of 0 or 1.
8. No evidence of metastasis or recurrence on postoperative imaging before enrollment.
9. Adequate organ function, defined as hematologic, hepatic, renal, and thyroid function meeting the protocol-specified criteria based on laboratory tests performed within 14 days before randomization.
10. Willing and able to comply with the study treatment, scheduled visits, laboratory tests, and other study procedures.
11. Female participants of childbearing potential must have a negative pregnancy test before enrollment and agree to use effective contraception during the study and for 6 months after the last dose of study treatment. Male participants with female partners of childbearing potential must agree to use effective contraception during the study and for 6 months after the last dose of study treatment.

Key Exclusion Criteria:

1. Presence of liver, peritoneal, or other distant metastases.
2. Inability to take oral medications.
3. Unresolved postoperative complications at the time of randomization, such as postoperative infection, anastomotic leakage or wound dehiscence, gastrointestinal bleeding, pancreatic fistula, or intestinal obstruction.
4. Uncontrolled pericardial effusion, uncontrolled pleural effusion, or clinically significant moderate or greater ascites at screening, defined as any of the following: pleural effusion or ascites with clinical symptoms and detectable by physical examination; or pleural effusion or ascites requiring drainage and/or intracavitary treatment during screening.
5. Underwent any surgery requiring general anesthesia that was not related to gastric cancer within 28 days before randomization.
6. History of or current diagnosis of another malignancy within 5 years.
7. Active or prior autoimmune disease that may relapse or require immunosuppressive treatment within 2 weeks or during the study period; or a history of immunodeficiency, including HIV positivity or other acquired or congenital immunodeficiency disease; or a history of organ transplantation.
8. Participation in another clinical study, or any condition that may interfere with the interpretation of the study results.
9. Any other severe acute or chronic disease that, in the investigator's judgment, may increase the risk associated with study participation or study treatment.
10. Active or uncontrolled infection requiring systemic antibiotic therapy within 2 weeks before randomization or at the time of randomization.
11. Diagnosis of interstitial pneumonia, noninfectious pneumonitis, pulmonary fibrosis, or acute lung disease.
12. Active tuberculosis within 1 year or previous anti-tuberculosis treatment.
13. Female participants who are pregnant, breastfeeding, or planning to become pregnant during treatment or within 6 months after the end of treatment.
14. History of psychotropic drug abuse with inability to discontinue, or presence of a psychiatric disorder.
15. Patients considered unsuitable for participation in this study by the investigator.

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

3

Arms and Interventions

Participant Group / Arm	Intervention / Treatment
Experimental: Cohort 1 Experimental Arm; Participants randomized to the cohort 1 experimental arm will switch to an alternative postoperative treatment regimen. The alternative regimen will be selected by the investigator based on the participant's preoperative treatment regimen, postoperative molecular subtype, and the 2025 CSCO and 2025 NCCN guidelines. The regimen should include taxane-based or irinotecan-based monotherapy or combination therapy that was not used before surgery. The administration schedule and dosage of adjuvant therapy will follow standard clinical practice guidelines and the relevant drug prescribing information.	Drug: Alternative Postoperative Treatment Regimen; Participants in this arm will switch to an alternative postoperative treatment regimen selected by the investigator according to prior neoadjuvant therapy, postoperative molecular subtype, and the 2025 CSCO and NCCN guidelines. The regimen will include taxane-based or irinotecan-based treatment that was not used before surgery, with dosage and administration based on clinical practice standards and drug prescribing information.
Active Comparator: Cohort 1 Control Arm; Participants randomized to the Cohort 1 control arm will continue treatment according to the preoperative treatment regimen. The administration schedule and dosage of adjuvant therapy will follow standard clinical practice guidelines and the relevant drug prescribing information.	Drug: Original Treatment Regimen; The original preoperative treatment regimen will be continued postoperatively. The administration schedule and dosage of adjuvant therapy will follow standard clinical practice guidelines and the relevant drug prescribing information.
Experimental: Cohort 2; Participants in Cohort 2 will undergo postoperative observation without routine antitumor drug therapy. They will receive regular follow-up monitoring according to the study protocol.	Other: Postoperative Observation; Participants will undergo postoperative observation without further antitumor drug therapy. Routine follow-up monitoring will be conducted according to the study protocol.

What is the study measuring?

Primary Outcome Measures

Outcome Measure	Measure Description	Time Frame
Median Event-Free Survival in Cohort 1（mEFS）	defined as the time from randomization to the first documented local, regional, or distant recurrence, or death from any cause, whichever occurs first.	Up to approximately 13 months
2-year Event-Free Survival Rate in Cohort 2（2-y EFS）	defined as the proportion of participants in Cohort 2 who are alive without documented local, regional, or distant recurrence at 2 years after cohort assignment.	Up to 2 years

Secondary Outcome Measures

Outcome Measure	Measure Description	Time Frame
1-year Event-Free Survival Rate in Cohort 1（1-y EFS）	defined as the proportion of participants in Cohort 1 who are alive without documented local, regional, or distant recurrence at 1 year after randomization.	Up to 1 year
1-Year Overall Survival Rate in Cohort 1（1-y OS）	defined as the proportion of participants in Cohort 1 who are alive at 1 year after randomization.	Up to 1 year
Median Overall Survival in Cohort 1（mOS）	defined as the time from randomization to death from any cause. Median overall survival will be evaluated in participants in Cohort 1.	Up to approximately 3 years
2-Year Overall Survival Rate in Cohort 2（2-y OS）	defined as the proportion of participants in Cohort 2 who are alive at 2 years after cohort assignment.	Up to 2 years
3-year Event-Free Survival Rate in Cohort 2（3-y EFS）	defined as the proportion of participants in Cohort 2 who are alive without documented local, regional, or distant recurrence at 3 years after cohort assignment.	Up to 3 years
3-year Overall Survival Rate in Cohort 2（3-y OS）	defined as the proportion of participants in Cohort 2 who are alive at 3 years after cohort assignment.	Up to 3 years
Incidence and Severity of Adverse Events	The incidence and severity of adverse events will be assessed according to NCI CTCAE version 5.0. Safety assessments will include adverse events, serious adverse events, vital signs, ECOG performance status, physical examination, electrocardiogram, echocardiography, and clinically significant changes from baseline in laboratory test results.	Up to approximately 3 years

Collaborators and Investigators

• Sponsor: Nanfang Hospital, Southern Medical University

Study record dates

Study Major Dates

• Study Start (Estimated): June 1, 2026
• Primary Completion (Estimated): August 1, 2029
• Study Completion (Estimated): December 1, 2029

Study Registration Dates

• First Submitted: May 18, 2026
• First Submitted That Met QC Criteria: May 18, 2026
• First Posted (Actual): May 22, 2026

Study Record Updates

• Last Update Posted (Actual): May 22, 2026
• Last Update Submitted That Met QC Criteria: May 18, 2026
• Last Verified: May 1, 2026

More Information

Terms related to this study

• Keywords: Prognosis; Gastric cancer; Gastroesophageal junction cancer; Neoadjuvant therapy; Pathological response; Adaptive adjuvant therapy
• Additional Relevant MeSH Terms: Neoplasms by Site; Neoplasms; Gastrointestinal Neoplasms; Digestive System Neoplasms; Digestive System Diseases; Gastrointestinal Diseases; Stomach Diseases; Stomach Neoplasms
• Other Study ID Numbers: NFEC-2026-306

Plan for Individual participant data (IPD)

• Plan to Share Individual Participant Data (IPD)?: UNDECIDED

Drug and device information, study documents

• Studies a U.S. FDA-regulated drug product: No
• Studies a U.S. FDA-regulated device product: No