Inclusion Criteria:
1. Subjects voluntarily participate in this study, sign the written informed consent form, and demonstrate good compliance.
2. Aged 18-80 years old at the time of signing informed consent, male or female.
3. Histologically confirmed stage IV non-small-cell lung cancer (NSCLC) according to the 8th IASLC/AJCC TNM staging system, with negative actionable driver gene alterations (EGFR/ALK/ROS1), and no prior systemic anti-cancer treatment.
4. Provide archived tumor tissue samples or newly obtained core/excisional biopsy specimens from tumor lesions which have not received prior anti-tumor therapy or radiotherapy. Formalin-fixed paraffin-embedded (FFPE) tissue blocks are preferred over slides; newly-obtained biopsy samples are preferred over archived tissues. PD-L1 expression ≥1% is confirmed by immunohistochemistry. For subjects without newly-obtained tissue, 5-8 slices of 3-5 μm paraffin sections of archived tissue collected within 2 years before enrollment are acceptable.
5. Have at least one radiologically measurable lesion per RECIST version 1.1: target lesion with longest diameter ≥10 mm on CT/MRI, or pathologically enlarged lymph node with short-axis diameter ≥15 mm on CT scan.
6. Eastern Cooperative Oncology Group (ECOG) performance status of 0-1.
7. Expected survival time ≥ 3 months.
8. Treatment-naive patients without previous systemic anti-tumor therapy (including radiotherapy, chemotherapy, targeted or immunotherapy), or patients with disease recurrence more than 6 months after completion of postoperative adjuvant chemotherapy.
9. Adequate organ and bone marrow function confirmed by laboratory tests obtained within 7 days before enrollment. No blood product transfusion, growth factors, albumin or other corrective medications are permitted within 14 days prior to laboratory assessment:
1\) Hematology: absolute neutrophil count (ANC) ≥1.5×10⁹/L, platelet count (PLT) ≥75×10⁹/L, hemoglobin (HGB) ≥90 g/L (no transfusion or erythropoietin-dependency within 14 days); 2) Liver function: total bilirubin (TBIL) ≤2×ULN; alanine aminotransferase (ALT) and/or aspartate aminotransferase (AST) ≤5×ULN; serum albumin ≥28 g/L; alkaline phosphatase (ALP) ≤5×ULN; 3) Renal function: serum creatinine (Cr) ≤1.5×ULN, or creatinine clearance ≥50 mL/min using Cockcroft-Gault formula; urine protein \<2+ on urinalysis. For baseline urine protein ≥2+, 24-hour urine protein quantification must be \<1 g.
4\) Coagulation function: international normalized ratio (INR) or prothrombin time (PT) ≤1.5×ULN. For subjects receiving anticoagulants, INR within the therapeutic target range of anticoagulation is acceptable.
10\. For women of child-bearing potential, negative urine or serum pregnancy test within 3 days prior to first study drug administration.
11\. Tissue samples must be available for biomarker (e.g. PD-L1) analysis. Newly-obtained specimens are preferred; archived paraffin sections obtained within 2 years before enrollment are allowed if fresh tissue cannot be acquired.
Exclusion Criteria:
1. Tumor invades major blood vessels on CT/MRI, or judged to carry high risk of invading critical vessels and causing fatal hemorrhage during study treatment.
2. Currently participating in another interventional clinical trial, or received investigational drug/device within 4 weeks before first study drug administration.
3. Received anti-tumor Chinese patent medicine or immunomodulatory agents (such as thymosin, interferon, interleukin) within 2 weeks prior to first dose; or underwent major surgical operation within 3 weeks before first dose.
4. Active hemoptysis requiring clinical intervention, active diverticulitis, intra-abdominal abscess, gastrointestinal obstruction, or peritoneal metastasis.
5. Any bleeding diathesis regardless of severity; any bleeding/hemorrhagic event ≥ CTCAE grade 3 within 4 weeks before enrollment; unhealed wound, ulcer or fracture.
6. New York Heart Association (NYHA) class III-IV congestive heart failure, or uncontrolled clinically significant arrhythmia.
7. History of arterial thrombosis, embolism or ischemic events within 6 months before study entry, such as myocardial infarction, unstable angina, cerebrovascular accident or transient ischemic attack.
8. Known hypersensitivity to any study drug.
9. Require chronic systemic corticosteroid therapy. Intermittent bronchodilators, inhaled corticosteroids for COPD/asthma, or local corticosteroid injection are permitted.
10. Symptomatic central nervous system (CNS) metastases. Patients with asymptomatic or treated-stable brain metastases may be enrolled only if all of the following criteria are met: measurable extracranial lesion; no midbrain, pons, cerebellum, meningeal, medulla oblongata or spinal cord metastasis; clinically stable for at least 2 weeks; systemic steroid discontinued at least 3 days before first study drug dose.
11. Active infection requiring treatment, or systemic anti-infective medication administered within 1 week before first dose. Subjects have not sufficiently recovered from toxicity/complications induced by prior interventions (≤ grade 1 or return to baseline, excluding fatigue and alopecia).
12. Known human immunodeficiency virus (HIV-1/2 antibody positive).
13. Untreated active hepatitis B (HBsAg positive with HBV-DNA above local laboratory upper limit of normal). Subjects with HBV viral load \<1000 copies/mL (200 IU/mL) are eligible and should receive anti-HBV prophylaxis during study therapy to prevent viral reactivation. Anti-HBc positive, HBsAg negative, anti-HBs negative and HBV-DNA negative subjects do not require prophylactic anti-HBV therapy but need close monitoring for viral reactivation.
14. Active hepatitis C infection (HCV-Ab positive with HCV-RNA above assay lower limit).
15. Received live-attenuated vaccine within 30 days before Cycle 1 Day 1. Seasonal inactivated injectable influenza vaccine within 30 days before first dose is allowed; intranasal live-attenuated influenza vaccine is prohibited.
16. Pregnant or breastfeeding women.
17. Medical history, disease condition, treatment or laboratory abnormality that may interfere with study results or prevent full participation in the trial; or other conditions judged by the investigator to render the subject unsuitable for enrollment or associated with potential safety risks.
