Eligibility
Inclusion Criteria:
* All trial participants or their legally acceptable representatives must sign the Ethics Committee-approved informed consent form before any screening procedures are initiated.
* Aged 18 to 85 years (inclusive) at the time of signing the informed consent, regardless of gender.
* ECOG performance status of 0 to 1.
* Histologically or cytologically confirmed unresectable locally advanced or metastatic squamous non-small cell lung cancer (NSCLC). Mixed pathology including small cell lung cancer or other pathological components must be excluded.
* Must have received prior first-line systemic anti-tumor therapy, including: a) platinum-based doublet chemotherapy; b) immunotherapy (including but not limited to monoclonal antibodies targeting PD-1, PD-L1, CTLA-4, or their bispecific antibodies).
* Radiologically confirmed disease progression during or within 6 months after discontinuation of the most recent treatment regimen.
* Archived tumor tissue samples must be provided.
* Expected survival of ≥ 3 months.
* At least one measurable lesion per RECIST v1.1 criteria at screening. For those with a clear history of radiotherapy, measurable lesions must be outside the radiation field or have shown clear progression after completion of radiotherapy.
* Organ function of trial participants must meet certain criteria.
* Subjects with reproductive potential must take effective contraceptive measures during the trial and for 180 days after the last dose. Female subjects must be confirmed non-pregnant before enrollment, and lactating females must stop breastfeeding, unless surgically sterilized, postmenopausal, or without reproductive potential.
* Able to understand and comply with planned visits, treatment, laboratory tests, and other study procedures.
Exclusion Criteria:
* Received radiotherapy, chemotherapy, or other anti-tumor treatments within 21 days before the first dose; received anti-tumor traditional Chinese medicine within 7 days; received other investigational drugs or devices not yet on the market within 28 days; previously received antibody-drug conjugates (ADCs) or docetaxel.
* Positive for clinically significant driver gene mutations, including EGFR, KRAS, ALK, ROS1, BRAF, NTRK, MET, RET, HER2.
* Persistent clinically significant toxicities of Grade ≥ 2 related to prior therapy (excluding alopecia and Grade 2 immune-related endocrine toxicities requiring stable doses of replacement therapy).
* Trial participants with clinically symptomatic effusions requiring local therapy or repeated drainage (pleural effusion, ascites, pericardial effusion, etc.).
* Underwent major surgery within 28 days before the first dose of study drug, excluding minor surgeries judged by the investigator as not affecting participation in the trial.
* Received live vaccines within 28 days before the first dose of study drug, or plan to receive any live vaccines during the study period.
* Clinically significant cardiovascular or cerebrovascular diseases within 6 months before the first study drug administration, including but not limited to: acute myocardial infarction, unstable angina, cerebrovascular accident, clinically significant ventricular arrhythmia, NYHA Class III/IV heart failure, QTcF ≥ 470 ms (female) / 450 ms (male), history of long QT syndrome, LVEF \< 50% or severe wall motion abnormality, uncontrolled hypertension (systolic blood pressure \> 160 mmHg or diastolic blood pressure \> 100 mmHg), or other unsuitable arrhythmias.
* History of pulmonary disease requiring steroid therapy; active pulmonary tuberculosis within 1 year before the first study drug administration; pulmonary embolism, severe asthma, or severe chronic obstructive pulmonary disease within 3 months; autoimmune or inflammatory diseases involving the lungs; history of prior pneumonectomy on one side.
* History of gastrointestinal perforation or fistula within 6 months before the first study drug administration, or active gastric/duodenal ulcer, ulcerative colitis, or other gastrointestinal diseases that the investigator considers may cause bleeding or perforation.
* Uncontrolled active bleeding or known bleeding tendency. If imaging shows tumor invasion of major blood vessels or unclear boundaries, or if the investigator judges that the tumor is highly likely to invade important blood vessels during the subsequent study period causing fatal massive bleeding.
* History of deep vein thrombosis, pulmonary embolism, or any other severe thromboembolic event within 3 months before the first study drug administration; portal vein tumor thrombus involving both the main trunk and bilateral first-order branches, or involving both the main trunk and superior mesenteric vein, or inferior vena cava tumor thrombus.
* Presence of any of the following infections: ① Hepatitis B virus; ② Hepatitis C virus; ③ Human immunodeficiency virus; ④ Active Mycobacterium tuberculosis infection; ⑤ Other active infections requiring systemic intravenous anti-infective treatment occurring within 14 days before the first study drug administration; ⑥ Active syphilis infection.
* Subjects with central nervous system (CNS) metastases and/or carcinomatous meningitis. Subjects who have received treatment for brain metastases or have small, asymptomatic, incidental, untreated lesions may be considered for participation, provided that clinical symptoms are stable for at least 4 weeks before study drug administration, no disease progression is confirmed by imaging within 4 weeks before the first dose, all neurological symptoms have completely resolved, no evidence of new or enlarged brain metastases, and radiation, surgery, or steroid therapy was discontinued at least 28 days before the first dose of study treatment. Carcinomatous meningitis and meningeal compression should be excluded regardless of clinical stability.
* Other malignancies within 3 years before the first dose of study drug, except for cured cancers.
* Active autoimmune diseases within 6 months before the first dose of study drug. Subjects with hypothyroidism requiring only stable doses of replacement therapy or skin diseases not requiring systemic treatment are eligible.
* Use of systemic immunosuppressive agents within 2 weeks before the first dose of study drug, excluding: topical glucocorticoids, physiological doses of systemic glucocorticoids, or glucocorticoids used as prophylaxis for hypersensitivity reactions.
* Known history of allogeneic organ transplantation and allogeneic hematopoietic stem cell transplantation.
* History of drug abuse or psychiatric illness, or suspected allergy or intolerance to the study drug or any of its components.
* Other conditions judged by the investigator as unsuitable for participation in the study.