A Study of Bemotuzumab Plus Chemotherapy and Anlotinib Induction Followed by Bemotuzumab, Anlotinib and Consolidative Thoracic Radiotherapy in Extensive-Stage Small Cell Lung Cancer

\*\*Inclusion Criteria:\*\*

1. Histologically or cytologically confirmed extensive-stage small cell lung cancer (ES-SCLC) per VALG staging.
2. No prior systemic therapy for ES-SCLC.
3. At least one measurable lesion as defined by RECIST 1.1 criteria.
4. Age 18-75 years.
5. ECOG performance status of 0-2.
6. Life expectancy of ≥3 months.
7. Adequate hematologic and organ function:

   * Absolute neutrophil count (ANC) ≥ 1.5 × 10\^9/L.
   * Platelet count ≥ 100 × 10\^9/L.
   * Hemoglobin ≥ 80 g/L.
   * Creatinine clearance ≥ 50 mL/min.
   * Total bilirubin ≤ 1.5 × upper limit of normal (ULN).
   * AST and ALT ≤ 2.5 × ULN.
   * Albumin ≥ 28 g/L.
   * INR and APTT ≤ 1.5 × ULN.
   * Left ventricular ejection fraction (LVEF) ≥ 50%.
8. For females of childbearing potential: negative serum pregnancy test within 3 days prior to dosing and agreement to use highly effective contraception.
9. For males: agreement to use barrier contraception.
10. Willing and able to provide written informed consent and comply with study procedures.

\*\*Exclusion Criteria:\*\*

1. Symptomatic brain metastases. (Asymptomatic, treated, and stable brain metastases for ≥1 month without steroids are allowed).
2. Prior thoracic radiotherapy for SCLC.
3. Prior treatment with anti-angiogenic agents (e.g., anlotinib, bevacizumab) or anti-PD-1/PD-L1 therapies.
4. Factors affecting oral medication intake (e.g., inability to swallow, major gastrointestinal resection).
5. Uncontrolled effusions requiring repeated drainage (pleural, pericardial, or ascites).
6. Imaging evidence of tumor invasion of major blood vessels or high risk of fatal hemorrhage as judged by the investigator.
7. History of significant bleeding tendency or coagulopathy, including clinically significant hemoptysis (\>1 tablespoon daily within 3 months) or significant bleeding within 4 weeks prior to enrollment.
8. Major surgical procedure, open biopsy, or significant traumatic injury within 28 days prior to enrollment.
9. Arterial/venous thrombotic events within 6 months prior to enrollment (e.g., cerebrovascular accident, deep vein thrombosis, pulmonary embolism).
10. Active autoimmune disease requiring systemic treatment within 2 years prior to first dose.
11. Any other condition that, in the investigator's judgment, increases risk or renders the patient unsuitable for the study.