A Single-arm, Exploratory Clinical Study Evaluating the Efficacy and Safety of Bevacizumab in Combination With Anlotinib and Etoposide as First-line Therapy for Elderly Patients With Small-cell Lung Cancer or Those Who Are Intolerant to Intensive Chemotherapy

A single-arm exploratory clinical study to observe and evaluate the first-line treatment of elderly and treatment-intolerant patients with small cell lung cancer using benmelstobart in combination with anlotinib and etoposide. Eligible patients are those with histologically or pathologically confirmed small cell lung cancer (SCLC) (AJCC 9th edition), who are treatment-naïve and considered elderly or intolerant to intensive therapy. Eligible subjects receive 4-6 cycles of benmelstobart injection combined with anlotinib hydrochloride and etoposide, followed by maintenance therapy with benmelstobart injection plus anlotinib hydrochloride, continued until disease progression or intolerable toxicity. The study aims to evaluate the efficacy and safety of first-line treatment with benmelstobart injection in combination with anlotinib hydrochloride and etoposide in patients with advanced SCLC.

Inclusion Criteria: 1. The subject must voluntarily participate in this study after being fully informed and must sign a written informed consent form (ICF), and be willing and able to comply with the study procedures and requirements. 2. At the time of signing the ICF, male or female subjects aged ≥65 years, or male or female subjects aged ≥18 years who are assessed by the investigator as not suitable for intensive treatment, defined as: ECOG performance status of 2-3, or comorbidities (CIRS \>6 and ≤12), or otherwise judged by the investigator as not suitable for intensive treatment. Intensive treatment is defined as first-line intensive therapy for metastatic small cell lung cancer, i.e., standard chemotherapy with etoposide plus cisplatin or carboplatin combined with immune checkpoint inhibitors and targeted agents. 3. Histologically or cytologically confirmed metastatic small cell lung cancer (SCLC), according to the International Association for the Study of Lung Cancer and the American Joint Committee on Cancer TNM staging system, 9th edition (AJCC 9th). 4. Subjects must not have received prior systemic therapy for metastatic SCLC. Patients who previously received adjuvant, neoadjuvant, or radical chemoradiotherapy for non-metastatic disease are eligible if disease progression occurred \>6 months after completion of the last treatment. 5. At least one measurable target lesion according to RECIST v1.1. Lesions previously treated with radiotherapy or other local regional therapy are not considered target lesions unless clear progression is documented after treatment. Lesions must have a longest diameter ≥10 mm on CT or MRI at baseline (lymph nodes must have a short axis ≥15 mm), and must be suitable for repeated accurate measurement per RECIST v1.1. 6. Eastern Cooperative Oncology Group (ECOG) performance status of 0-3. 7. Adequate organ function as defined below, with no blood transfusion or use of hematopoietic growth factors within 14 days prior to testing: Platelets (PLT) ≥80 × 10⁹/L Hemoglobin (HGB) ≥80 g/L Neutrophils (NEUT) ≥1.5 × 10⁹/L Creatinine ≤1.5 × upper limit of normal (ULN) or creatinine clearance (CrCl) ≥30 mL/min (Cockcroft-Gault) ALT and AST ≤2.5 × ULN (≤5 × ULN if liver metastases present) Total bilirubin (TBIL) ≤1.5 × ULN (≤3 × ULN in Gilbert's syndrome) INR or PT ≤1.5 × ULN and APTT ≤1.5 × ULN, or clinically acceptable bleeding risk as assessed by investigator Urine protein \