This is a multicenter, randomized, open-label, controlled phase III clinical study to evaluate the efficacy and safety of HS-20093- injection versus investigator's choice of chemotherapy in patients with locally advanced or metastatic esophageal squamous cell carcinoma after progress of first-line standard therapy.

This is a multicenter, randomized, open-label, controlled phase III clinical study to evaluate the efficacy and safety of HS-20093- injection versus investigator's choice of chemotherapy in patients with locally advanced or metastatic esophageal squamous cell carcinoma after progress of first-line standard therapy.

Eligible participants will be randomly assigned in a 1:1 ratio to the experimental arm (HS-20093) or the control arm (investigator's choice of monochemotherapy, including irinotecan, paclitaxel, or docetaxel). Both experimental arm and control arm will receive a treatment cycle of 21 days until disease progression or other treatment discontinuation criteria are met; Efficacy and safety will be analyzed and evaluated in both arms following the protocol-specified follow-up procedure.

Inclusion Criteria:

1. Age ≥18 years at the time of informed consent form (ICF) signature, either sex.
2. Be willing to participate in this clinical trial with understanding of study procedures, ability to provide written informed consent, and commitment to comply with all requirements specified in this clinical trial protocol.
3. Patients with histologically or cytologically confirmed diagnosis of advanced recurrent or metastatic esophageal squamous cell carcinoma (ESCC), progressed after receiving first-line standard treatment.
4. Presence of at least one target lesion according to RECIST v1.1.
5. Eastern Cooperative Oncology Group performance status (ECOG PS) score of 0 to 1.
6. Minimum life expectancy >12 weeks.
7. Adequate organ function.
8. Absence of the following active infectious diseases: hepatitis B, hepatitis C, human immunodeficiency virus (HIV) infection, tuberculosis, or syphilis.
9. Female patients with negative serum pregnancy test result within 7 days prior to first dose administration, or documentation of no pregnancy risk.

Exclusion Criteria:

• 1. Prior pathological diagnosis of esophageal adenocarcinoma, esophageal adenoid cystic carcinoma, esophageal mucoepidermoid carcinoma, esophageal undifferentiated carcinoma, esophageal neuroendocrine carcinoma, or esophageal mixed carcinoma 2. Prior or ongoing treatment with any of the following:

  1. Prior or current treatment targeting B7-H3;

  2. Prior or current treatment with topoisomerase I inhibitor agents, including antibody-drug conjugates with topoisomerase I inhibitor payloads, etc.; 3. Persistent adverse reactions caused by prior treatment. 4. Untreated brain metastases; uncontrolled brain metastases; presence of leptomeningeal or brainstem metastases; presence of spinal cord compression.

     5. History of other primary malignancies. 6. Severe, uncontrolled, or active cardiovascular or cerebrovascular disease. 7. Severe or poorly controlled hypertension and diabetes mellitus. 8. Tumors have the risk of leading perforation/fistula, hemorrhage, or obstruction.

     9. Known or suspected interstitial pneumonitis, immune-mediated pneumonitis, or radiation pneumonitis.

     10. Known to have allergic reactions or contraindications to the investigational medicinal product.