Efficacy and Safety of Paclitaxel Polymeric Micelles in Patients With Recurrent/Metastatic Head and Neck Squamous Cell Carcinoma

Inclusion Criteria: * Age ≥18 and ≤75 years, male or female; Histologically or cytologically confirmed head and neck squamous cell carcinoma; Prior first-line systemic therapy (including chemotherapy, targeted therapy, and immunotherapy) with disease progression or judged by the clinician to no longer derive clinical benefit; ECOG performance status score of 0-2 and a life expectancy of at least 3 months; At least one measurable lesion on imaging according to the Response Evaluation Criteria in Solid Tumors (RECIST v1.1, Appendix 3); Adequate major organ function, with subjects meeting the following laboratory parameters: Complete blood count meeting the following criteria (no blood transfusion, blood products, granulocyte colony-stimulating factor, or other hematopoietic growth factors within 7 days prior to the test): WBC ≥3.0×10\^9/L, ANC ≥1.5×10\^9/L, platelets ≥100×10\^9/L, hemoglobin ≥90 g/L; Blood biochemistry meeting the following criteria: total bilirubin ≤1.5×ULN, AST, ALT, or ALP ≤2.5×ULN (for subjects with liver metastases, ALT, AST, or ALP ≤5×ULN is permitted; for subjects with bone metastases, ALP ≤10×ULN is permitted); serum creatinine ≤1.5×ULN and creatinine clearance (calculated using the Cockcroft-Gault formula, Appendix 4) ≥50 mL/min; Adequate coagulation function, defined as INR ≤1.5×ULN and PT or APTT ≤1.5×ULN; Subjects of childbearing potential must agree to use highly effective contraceptive measures during the trial. Women of childbearing potential must have a negative serum or urine pregnancy test within 72 hours prior to the start of chemotherapy; Good compliance, able to undergo treatment and follow-up, and willing to comply with the study requirements; voluntary signing of the informed consent form. Exclusion Criteria: * Known allergy or intolerance to any study treatment or any excipient; Presence of uncontrolled serious medical conditions, such as severe comorbidities including severe cardiac disease, cerebrovascular disease, uncontrolled diabetes, uncontrolled hypertension, uncontrolled infection, active peptic ulcer, etc.; Other malignancies within the past 5 years, except for adequately treated basal cell or squamous cell skin cancer, localized prostate cancer after radical surgery, or ductal carcinoma in situ after radical surgery; Requirement for concomitant use of other antineoplastic drugs; Receipt of any other investigational drug or participation in another interventional clinical trial within 30 days prior to screening; History of psychotropic substance abuse with inability to abstain, or presence of psychiatric disorders; Pregnant or breastfeeding women; Patients deemed unsuitable for enrollment by the investigator.