Adjuvant Therapy for Potentially Immunotherapy-Responsive Gastric or Gastroesophageal Junction Adenocarcinoma

NCT07772557 | Not Yet Recruiting Phase 2

• 1 other identifier: 2026-SR-531
• Study Type: interventional
• Target: 108
• Locations: 0 countries
• Sites: N/A

Brief Summary

This study evaluates the clinical efficacy and safety benefits of immunotherapy in a selected patient population by comparing serplulimab combined with short-course SOX regimen versus SOX regimen alone as adjuvant therapy for patients with stage pII-III gastric or gastroesophageal junction (G/EGJ) adenocarcinoma who are PD-L1 CPS ≥5, EBV-positive, or dMMR/MSI-H.

Conditions

Gastric or Gastroesophageal Junction Adenocarcinoma

Outcome Measures

Primary Outcomes (1)

• 3yr-RFS rate

  Defined as the proportion of patients who have not developed local or regional recurrence or distant metastasis from randomization to the 3-year follow-up, excluding second primary malignancies and non-tumor-related deaths.

  from randomization to the 3-year follow-up

Secondary Outcomes (3)

• Recurrence-Free Survival (RFS)

  from randomization until the date of first documented occurrence of local or regional recurrence or distant metastasis, whichever came first,Up to 5 years

• Overall Survival (OS)

  From date of randomization until the date of first documented date of death from any cause，Up to 5 years.

• Safety

  All subjects should continue to undergo safety assessments and adverse event follow-up for 90 days after the last dose, and concomitant treatments should be recorded.

Study Arms (2)

Standard Treatment Group

ACTIVE COMPARATOR

Standard Treatment Group: SOX regimen for up to 6 cycles Oxaliplatin: 130 mg/m², i.v., D1, Q3W; S-1 (Tegafur-Gimeracil-Oteracil Potassium): Oral administration: 40 mg per dose for BSA \< 1.25, 50 mg per dose for BSA ≥ 1.25 to \< 1.5, 60 mg per dose for BSA ≥ 1.5, twice daily, administered from D1 to D14 of each cycle, Q3W, for up to 6 cycles postoperatively.

Drug: Standard Treatment Group: SOX regimen for up to 6 cycles Oxaliplatin: 130 mg/m², i.v., D1, Q3W; S-1 (Tegafur-Gimeracil-Oteracil Potassium): Oral administration: 40 mg per dose for BSA < 1.25, 50 mg pe

Experimental Immunotherapy Group

EXPERIMENTAL

Experimental Immunotherapy Group: Phase I: Combination Therapy Period (First 3 Cycles) Oxaliplatin: 130 mg/m², intravenous infusion, Day 1, every 3 weeks (Q3W), for 3 cycles. Serplulimab: 300 mg, intravenous infusion, Day 1, every 3 weeks (Q3W), administered concurrently with oxaliplatin. S-1 (Tegafur-Gimeracil-Oteracil Potassium): Same administration regimen as the control group (oral, D1-D14, Q3W), for 3 cycles. Phase II: Immunotherapy Maintenance Period (From Cycle 4 Onward) Serplulimab: 300 mg, intravenous infusion, Day 1, every 3 weeks (Q3W), continued until 1 year post-surgery or until radiographic confirmation of tumor recurrence or metastasis.

Drug: Experimental Immunotherapy Group: Phase I: Combination Therapy Period (First 3 Cycles) Oxaliplatin: 130 mg/m², intravenous infusion, Day 1, every 3 weeks (Q3W), for 3 cycles. Serplulimab: 300 mg, i

Interventions

Standard Treatment Group: SOX regimen for up to 6 cycles Oxaliplatin: 130 mg/m², i.v., D1, Q3W; S-1 (Tegafur-Gimeracil-Oteracil Potassium): Oral administration: 40 mg per dose for BSA < 1.25, 50 mg pe DRUG

SOX

Standard Treatment Group

Experimental Immunotherapy Group: Phase I: Combination Therapy Period (First 3 Cycles) Oxaliplatin: 130 mg/m², intravenous infusion, Day 1, every 3 weeks (Q3W), for 3 cycles. Serplulimab: 300 mg, i DRUG

Serplulimab+SOX

Experimental Immunotherapy Group

Eligibility Criteria

• Age: 18 Years - 75 Years
• Sex: all
• Healthy Volunteers: No
• Age Groups: Adult (18-64), Older Adult (65+)

You may qualify if:

• The patient voluntarily joins this study and signs the informed consent form.
• Age ≥18 years and ≤75 years, male or female.
• Histologically confirmed gastric or gastroesophageal junction (GEJ) adenocarcinoma (predominantly adenocarcinoma) with stage II-III disease (TNM staging, 8th UICC/AJCC) who have not received preoperative neoadjuvant therapy.
• ECOG performance status: 0-1.
• Postoperative testing of gastric cancer specimens indicates: PD-L1 CPS ≥5, or EBV-positive, or dMMR.
• No prior anti-tumor therapy for gastric cancer, including chemotherapy, targeted therapy, immunotherapy, or local radiotherapy.
• Female patients of childbearing potential (not surgically sterilized) must use a medically acceptable contraceptive method (e.g., intrauterine device, contraceptive pills, or condoms) during the study treatment period and for 3 months after the end of the study treatment. Female patients of childbearing potential must have a negative serum or urine HCG test within 72 hours prior to study enrollment and must not be breastfeeding. Male patients must be surgically sterilized or agree to use an appropriate contraceptive method during the study period and for 3 months after the last dose of the investigational drug.
• Baseline hematological and biochemical parameters must meet the following criteria:
• Hemoglobin ≥90 g/L; Absolute neutrophil count ≥1.5×10⁹/L; Platelet count ≥100×10⁹/L; Hepatic function: ALT ≤2.5×ULN, AST ≤2.5×ULN, TBIL ≤1.5×ULN (for patients with liver metastases: ALT ≤5×ULN, AST ≤5×ULN, TBIL ≤3×ULN); Renal function: Creatinine ≤1.5×ULN, or when creatinine \>1.5×ULN, endogenous creatinine clearance \>50 mL/min; Alkaline phosphatase ≤2.5×ULN; Thyroid-stimulating hormone (TSH) ≤1×ULN (if abnormal, T3 and T4 levels should be evaluated; patients may be enrolled if T3 and T4 levels are within normal limits).

You may not qualify if:

• Pregnant or breastfeeding women.
• Women of childbearing potential with a positive baseline pregnancy test.
• Distant metastasis diagnosed by CT/MRI/EUS.
• Prior anti-tumor therapy, including chemotherapy, radiotherapy, or immunotherapy.
• Diagnosis of another malignancy within the past 5 years (excluding basal cell or squamous cell carcinoma, superficial bladder cancer, carcinoma in situ of the cervix, or breast cancer).
• Uncontrolled pleural effusion, pericardial effusion, or ascites.
• Severe cardiovascular disease within 12 months prior to enrollment, such as symptomatic coronary artery disease, congestive heart failure ≥ Class II, uncontrolled arrhythmia, or myocardial infarction.
• Concurrent upper gastrointestinal obstruction/bleeding, or digestive dysfunction/malabsorption syndrome that may affect the absorption of S-1.
• Concurrent severe uncontrolled infection or other severe uncontrolled concomitant disease, moderate or severe renal impairment.
• History of allergic reactions to any of the study drugs.
• Use of corticosteroids or other systemic immunosuppressive therapy within 14 days prior to enrollment.
• Receipt of an investigational drug within 4 weeks prior to enrollment (participation in another clinical trial).
• Active autoimmune disease (including but not limited to: uveitis, enteritis, hepatitis, hypophysitis, nephritis, vasculitis, hyperthyroidism, hypothyroidism, and asthma requiring bronchodilator therapy). Subjects with hypothyroidism requiring only hormone replacement therapy, or skin conditions not requiring systemic treatment (e.g., vitiligo, psoriasis, or alopecia), may be enrolled.
• History of primary immunodeficiency.
• Use of immunosuppressive agents within 4 weeks prior to the first dose of study treatment, excluding nasal sprays, inhaled, or other topical corticosteroids, or physiological doses of systemic corticosteroids (i.e., not exceeding 10 mg/day of prednisone or equivalent), or prophylactic use of corticosteroids for contrast allergy.

Sponsors & Collaborators

• The First Affiliated Hospital with Nanjing Medical University: lead

MeSH Terms

Interventions

S 1 (combination); Oxaliplatin; Infusions, Intravenous

Intervention Hierarchy (Ancestors)

Coordination Complexes; Organic Chemicals; Administration, Intravenous; Drug Administration Routes; Drug Therapy; Therapeutics; Infusions, Parenteral

Central Study Contacts

Hao XU

CONTACT

86-2568306505; liuhongda@njmu.edu.cn

Study Design

• Study Type: interventional
• Phase: phase 2
• Allocation: RANDOMIZED
• Masking: NONE
• Purpose: TREATMENT
• Intervention Model: PARALLEL
• Sponsor Type: OTHER
• Responsible Party: PRINCIPAL INVESTIGATOR
• PI Title: Professor

Study Record Dates

• First Submitted: August 7, 2026
• First Posted: August 19, 2026
• Study Start: September 1, 2026
• Primary Completion (Estimated): December 31, 2031
• Study Completion (Estimated): January 20, 2032
• Last Updated: August 19, 2026

Record last verified: 2026-08