Oncolytic Virus in Esophageal Squamous Cell Carcinoma

This clinical trial is designed to evaluate the preliminary efficacy and safety of an oncolytic virus combined with chemotherapy and an immune checkpoint inhibitor in patients with initially unresectable, locally advanced esophageal squamous cell carcinoma (ESCC). The primary endpoints are safety, surgical conversion rate and event-free survival (EFS). Secondary endpoints include overall survival (OS), objective response r ate (ORR), and quality of life (QoL). Exploratory endpoints include biomarker analyses such as single-cell sequencing.

**Participant Procedures**:

1.All participants must undergo diagnostic endoscopy at West China Hospital to confirm eligibility. 2.Participants will undergo eligibility assessments. Once eligibility is confirmed, written informed consent will be obtained. 3.Single-cell sequencing of primary tumors or metastatic lymph nodes will be performed. All study-related costs will be covered by the research budget. 4.Participants will receive two to four cycles of the investigational treatment regimen (oncolytic virus + chemotherapy + PD-1 inhibitor), with each cycle lasting 21 days. Upon completion, patients will enter routine follow-up with healthcare professionals to monitor long-term safety and health status.

Inclusion criteria

• A. Age 18-80 years B. Diagnosed with locally advanced esophageal squamous cell carcinoma (ESCC) with/without cervical lymph node metastases.

C. Ability to provide fresh tumor tissue samples (baseline) D. Normal major organ function E. Performance status (PS) score ≤ 1 F. Patients of childbearing potential must use contraception G. Voluntary participation with signed informed consent H. Able to comply with the study protocol, follow-up schedule, and other protocol requirements.

Exclusion criteria

• A. Received prior antitumor chemotherapy, radiotherapy, or immunotherapy before the first-line treatment.

B. High risk of gastrointestinal bleeding, esophageal fistula, or esophageal perforation C. Poor nutritional status D. Immune-related adverse events during prior radical treatment, such as Grade ≥3 pneumonitis, myocarditis, etc.

E. Signs and symptoms of interstitial diseases F. Presence of any severe and/or uncontrolled medical conditions G. Presence of concurrent malignancies H. Presence of other autoimmune diseases, or prolonged use of immunosuppressants or steroids I. Difficulty in patient communication or inability to comply with long-term follow-up J. Other conditions deemed unsuitable by the investigator