Abstract Objective: This study aims to investigate the potential clinical impact of neoadjuvant immunotherapy in resectable esophageal squamous cell carcinoma (ESCC).

The efficacy and safety of combining the programmed death 1 (PD-1) inhibitor serplulimab with nab-paclitaxel and cisplatin as neoadjuvant therapy in patients with resectable ESCC will be evaluated. Methods and analysis: A prospective, single-center, open-label cohort study will enroll 80 patients, with 40 patients allocated to the experimental group and 40 patients to the control group. Patients in the experimental arm will undergo 3 cycles of neoadjuvant therapy comprising serplulimab, cisplatin, and nab-paclitaxel, while those in the control arm will receive 3 cycles of neoadjuvant therapy with cisplatin and nab-paclitaxel. The primary efficacy endpoint will be the assessment of pathological complete response (pCR) following neoadjuvant therapy. Secondary efficacy endpoints will include major pathological response (MPR), disease-free survival, objective response rate (ORR), and monitoring of adverse events (AEs).

Ethics: Ethics approval has been obtained from the Ethics Committee at the First Affiliated Hospital (Xijing Hospital) of Air force Military Medical University (KY20242052-C-1).

Inclusion criteria:

• The age range of the enrolled patients was 18-70 years;
• ECOG score 0-1 ;
• Patients with ESCC diagnosed by pathology (histology or cytology);
• Resectable IB-III (cT1b~3N1-2M0 or cT3~4aN0~1M0) stage per the 8th edition of clinical TNM staging;
• Measurable lesions (per RECIST 1.1 criteria: major tumor diameter on CT scan ≥10mm, short lymph node diameter on CT scan ≥15mm);
• No prior radiotherapy, chemotherapy, surgery, or targeted therapy;
• Surgical tolerance and ability to consume liquid diet without esophageal complications;
• Normal major organ function criteria: (1) Blood tests: ANC ≥ 1.5 × 109/L, PLT ≥ 100 × 109/L, HB ≥ 90 g/L; (2) Biochemical tests: TBIL≤1.5×ULN, ALT/AST≤ 2.5×ULN, serum creatinine ≤1.5×ULN, ALB ≥ 30 g/L; (3) Coagulation function: INR≤1.5×ULN, APTT≤1.5×ULN;
• Normal or mildly to moderately abnormal lung function suitable for EC surgery: A) VC%>60%, B) FEV1>1.2L, FEV1%>40%, C) DLCO>40%;
• Voluntary participation with informed consent and good compliance.

The exclusion criteria were as follows:

• Any current or past presence of autoimmune diseases;
• Patients with immune deficiency disorders like HIV infection, active hepatitis B (HBV DNA ≥ 500 IU/ML), hepatitis C (HCV antibody positive, and HCV-RNA above the detection limit), or co-infection with hepatitis B and hepatitis C;
• Patients who have taken immunosuppressive drugs within 14 days before enrollment; patients who experienced a weight loss of ≥10% within 6 months prior to enrollment, or have a BMI below 18.5kg/m2, or have a PG-SGA score indicating grade C;
• Patients who had attenuated live vaccines within 4 weeks before enrollment;
• History of other cancers;
• Patients with myocardial infarction within six months before enrollment or diagnosed with New York Heart Association grade ≥ II heart failure;
• Patients who have experienced severe infections or undergone allogeneic organ transplantation or hematopoietic stem cell transplantation within the 4 weeks preceding enrollment;
• Patients with substance abuse, alcohol consumption, or psychotropic substance use.