Becotatug Vedotin Plus Cisplatin and Radiotherapy in LA-ESCC

Prior treatment

• Patients with a prior history of surgery for esophageal squamous cell carcinoma.
• Patients with a prior history of fistula caused by primary tumor infiltration.
• Patients with a diagnosis of pulmonary fibrosis or interstitial pneumonia within 28 days prior to enrollment.
• Use of strong inhibitors or inducers of CYP3A4, CYP2C8, and UGT1A1.
• Participation in another clinical trial within 4 weeks prior to enrollment.

Other illness

• Diagnosis of any other malignancy within the past 5 years (excluding carcinoma in situ, basal cell carcinoma, etc.).
• Anyone allergic to any drug or any of its components in this regimen.
• Patients at high risk of gastrointestinal bleeding, esophageal fistula, or esophageal perforation.
• Active infections such as HIV; active chronic HBV/HCV (e.g., HBV DNA ≥ 10⁴ copies/mL or ≥ 2000 IU/mL) requiring antiviral and hepatoprotective therapy before enrollment. Enrollment is allowed only when HBV DNA decreases to \< 10⁴ copies/mL or \< 2000 IU/mL, with continued antiviral therapy and regular monitoring of liver function and HBV DNA levels.
• Severe psychiatric disorder.

Lab values

• Presence of major cardiovascular disease, including any of the following conditions:
  • Congestive heart failure (defined as New York Heart Association \[NYHA\] Class III or IV), myocardial infarction, unstable angina, coronary angioplasty, stent implantation, coronary artery bypass grafting, cerebrovascular accident (CVA), or hypertensive crisis within 6 months prior to enrollment.
  • History of clinically significant ventricular arrhythmias (e.g., sustained ventricular tachycardia, ventricular fibrillation, torsade de pointes).
  • Fridericia-corrected QT interval (QTcF) \> 450 msec in males or \> 470 msec in females.
  • History or family history of congenital long QT syndrome.
  • Arrhythmias requiring antiarrhythmic therapy (subjects with atrial fibrillation that has been controlled for more than 30 days prior to randomization may be enrolled).
  • History of deep vein thrombosis, pulmonary embolism, or any other serious thromboembolic event within 3 months prior to enrollment (thrombosis related to an implanted venous access port or catheter, or superficial venous thrombosis, is not considered "serious" thromboembolism).

Other

• Subjects with poor nutritional status, defined as BMI \< 18.5 kg/m² or PG-SGA score ≥ 9.
• Severe chronic diarrhea.
• Patients who, in the opinion of the investigator, are unsuitable for participation in this study.

• Subjects who are able to understand and voluntarily sign informed consent forms (ICFs).
• Male and female subjects at the age of ≥18 and ≤75 at the time of screening.
• Histologically confirmed esophageal squamous cell carcinoma staged as cT2-T4a, N0-N+, M0-M1 (M1 limited to supraclavicular lymph node metastasis only).
• Patients must have at least one measurable lesion as defined by RECIST version 1.1 criteria.
• Patients who have not received any prior anti-tumor treatment for esophageal cancer.
• ECOG score of 0 or 1.
• Life expectancy ≥ 3 months.
• Adequate organ function (no blood transfusion and no use of granulocyte colony-stimulating factor, or other hematopoietic stimulator support within 2 weeks before the first administration of the study drug) confirmed as evidenced by:
  • Absolute Neutrophil Count (ANC) ≥ 1.5×10\^9/L;
  • Hemoglobin (Hgb) ≥ 90 g/dl;
  • Platelets (Plt) ≥ 75×10\^9/L;
  • Bilirubin total ≤ 1.5 x ULN, or bilirubin direct \< ULN for patients with bilirubin total levels \>1.5 ULN;
  • AST/ALT ≤ 2.5 x ULN or ≤ 5.0 x ULN if liver metastases are present;
  • Serum creatinine \< 1.5 x ULN or creatinine clearance \> 50 mL/min (as calculated via Cockcroft-Gault formula based on the actual body weight of the subject ;
• Female subjects must not be pregnant or breastfeeding. Female or male subjects of childbearing potential must agree to practice effective contraceptive measures throughout the study period and for 6 months after completion of study treatment.