Benmelstobart Plus Anlotinib, Chemotherapy and Thoracic Radiation for Limited-Stage Small Cell Lung Cancer

Inclusion criteria

• 1: Histologically or cytologically confirmed inoperable limited-stage small cell lung cancer (LS-SCLC) (per VALG staging).

2: No prior systemic therapy for limited-stage small cell lung cancer

3: Presence of measurable lesions as defined by RECIST 1.1. A previously irradiated lesion may be considered measurable only if it has demonstrated clear progression after radiotherapy and is not the sole lesion

4: Age ≥ 18 and ≤ 75 years

5: ECOG performance status: 0-1

6: Expected survival ≥ 3 months

7: Adequate hematologic and organ function, defined as meeting the following criteria: a) Hematologic function (no transfusion of blood or blood products, no G-CSF or other hematopoietic growth factors within 14 days): i. Absolute neutrophil count (ANC) ≥ 1.5 × 10⁹/L (1,500/mm³); ii. Platelet count (PLT) ≥ 100 × 10⁹/L (100,000/mm³); iii. Hemoglobin (HB) ≥ 80 g/L. b) Renal function: i. Calculated creatinine clearance (CrCl) ≥ 50 mL/min; ii. Urine protein < 2+ or 24-hour urine protein quantification < 1.0 g. c) Hepatic function: i. Serum total bilirubin (TBil) ≤ 1.5 × ULN; ii. AST and ALT ≤ 2.5 × ULN; iii. Serum albumin (ALB) ≥ 28 g/L. d) Coagulation function: i. International normalized ratio (INR) and activated partial thromboplastin time (APTT) ≤ 1.5 × ULN. e) Cardiac function: i. Left ventricular ejection fraction (LVEF) ≥ 50%.

8: Subjects voluntarily participate in this study, provide written informed consent, demonstrate good compliance, and agree to comply with follow-up procedures.

Exclusion criteria

• 1: Prior use of anti-angiogenic agents such as anlotinib, apatinib, bevacizumab, or related immunotherapeutic agents targeting PD-1, PD-L1, etc

2: Presence of multiple factors affecting oral medication absorption (e.g., inability to swallow, status post gastrointestinal resection, chronic diarrhea, intestinal obstruction, etc.).

3: Uncontrolled pleural effusion, pericardial effusion, or ascites requiring repeated drainage.

4: Patients with imaging evidence of tumor invasion adjacent to major blood vessels, or judged by the investigator to have a high risk of fatal massive hemorrhage due to tumor invasion of major blood vessels during the subsequent study period.

5: History of severe bleeding tendency or coagulopathy, including but not limited to: clinically significant hemoptysis (more than one tablespoon per day) within 3 months prior to enrollment; or clinically significant bleeding symptoms or bleeding diathesis within 4 weeks prior to randomization, such as gastrointestinal bleeding, hemorrhagic gastric ulcer (including gastrointestinal perforation and/or fistula; however, patients with surgically repaired gastrointestinal perforation or fistula may be eligible), unhealed wounds, ulcers, or fractures, etc.

6: Undergoing major surgical treatment, incisional biopsy, or significant traumatic injury within 28 days prior to randomization.

7: History of arterial/venous thrombotic events within 6 months prior to randomization, such as cerebrovascular accident (including transient ischemic attack), deep vein thrombosis, and pulmonary embolism.

8: Development of active autoimmune disease requiring systemic therapy (e.g., disease-modifying agents, corticosteroids, or immunosuppressants) within 2 years prior to the first dose.

9: Any other conditions that, in the judgment of the investigator, would render the patient ineligible for study enrollment.