A Clinical Study to Evaluate the Efficacy and Safety of HLX26 (Anti-LAG-3 Monoclonal Antibody Injection) Combined With Serplulimab and Chemotherapy in Previously Untreated Advanced NSCLC Patients

Prior treatment

• Myocardial infarction and poorly controlled arrhythmia occurred within six months before the first administration of the study drug.
• Patients with previous or current interstitial pneumonia, pneumoconiosis, radiation pneumonitis, drug-related pneumonitis, or severe pulmonary function impairment that may interfere with the detection and management of suspected drug-related pulmonary toxicity.
• Require systemic treatment with corticosteroids (\> 10 mg/day prednisone or equivalent) or other immunosuppressive agents within 14 days prior to the first dose of the study products or during the study.

Other illness

• Subjects with other histopathological types including small cell lung cancer, neuroendocrine cancer or sarcoma.
• Have other malignant tumors within 3 years.
• Patients with active pulmonary tuberculosis.
• Patients who have known active autoimmune diseases or suspected auto-immue disease. Patients in stable condition and do not require systemic immunosuppressant therapy are allowed to be enrolled.
• Patients with a history of severe allergy to any monoclonal antibody products.

Lab values

• III - IV cardiac insufficiency per NYHA standard or left ventricular ejection fraction\<50%.
• Patients who have received any T-cell costimulatory agents or immune checkpoint blockade therapy, including but not limited to cytotoxic T lymphocyte-associated antigen-4 (CTLA-4) inhibitors, PD-1 inhibitors, PD-L1 inhibitors.

Other

• Pleural effusion, pericardial effusion or ascites that require clinical intervention.

• Stage IV (AJCC 8th Edition) non-small cell lung cancer confirmed by histology or cytology.
• No EGFR sensitive mutation or ALK, ROS1 rearrangement.
• Have not received systemic treatment for stage IV disease. For patients who have received adjuvant or neoadjuvant treatment, if the adjuvant/neoadjuvant treatment has been completed for at least 6 months, they are allowed to be enrolled.
• At least one measurable lesion evaluated by the investigator per RECIST v1.1.
• Subjects must provide qualified tumor tissue samples for the detection of PD-L1 and LAG-3 expression level.
• Have adequate organ function with expected survival period ≥ 12 weeks and ECOG score of 0 or 1.