Sacituzumab Tirumotecan plus Toripalimab as first-line treatment for recurrent or metastatic head and neck squamous cell carcinoma

Inclusion Criteria:

* Aged 18-75 years, regardless of gender; Histologically or cytologically confirmed newly diagnosed locally advanced, recurrent or metastatic head and neck squamous cell carcinoma (primary tumor sites include oropharynx, oral cavity, hypopharynx, and larynx) that cannot be cured by local treatment. No anti-tumor systemic treatment has been received in the recurrent or metastatic stage (systemic treatment as part of local advanced tumor treatment is allowed, provided that more than 6 months have passed from the end of treatment to the signing of informed consent); ECOG performance status of 0 or 1; Expected survival period ≥ 12 weeks; At least one measurable lesion according to RECIST 1.1 criteria. Lesions that have received previous radiotherapy can be used as measurable lesions if disease progression occurs; Availability of tumor tissue for PD-L1 detection (paraffin-embedded specimens within 2 years or fresh tumor tissue); PD-L1 CPS ≥ 1 and positive trop2 expression, detected by immunohistochemistry; For oropharyngeal cancer patients, P16 detection status, detected by IHC;

Normal function of major organs within 2 weeks before treatment, meeting the following criteria:

Bone marrow function: Hemoglobin ≥ 100g/L, white blood cell count ≥ 4.0×10\^9/L or neutrophil count ≥ 2.0×10\^9/L, platelet count ≥ 100×10\^9/L without blood transfusion or colony-stimulating factor support; Liver function: Serum total bilirubin level ≤ 1.5 times the upper limit of normal, aspartate transaminase (AST) and alanine transaminase (ALT) ≤ 1.5 times the upper limit of normal; Renal function: Serum creatinine level \< 1.5 times the upper limit of normal or creatinine clearance rate ≥ 60ml/min, blood urea nitrogen ≤ 200mg/L; Urinary protein \< +; if urinary protein is +, the 24-hour total protein must be \< 500mg; Blood glucose: Within the normal range and/or for diabetic patients, blood glucose is controlled in a stable state during treatment; Cardiac function: No myocardial infarction within 1 year; no unstable angina; no symptomatic severe arrhythmia; no cardiac insufficiency; For women of childbearing age, serum pregnancy test results must be negative within 7 days before the first administration of the trial drug; males with reproductive capacity or females with the possibility of pregnancy must use highly effective contraceptive methods (such as oral contraceptives, intrauterine devices, abstinence, or barrier contraception combined with spermicides) throughout the trial, and continue contraception for 12 months after the end of treatment; Subjects voluntarily participate in this study, sign the informed consent form, have good compliance, and cooperate with follow-up; Patients whom doctors believe can benefit from the treatment.

Exclusion Criteria:

* Disease progression occurring within 6 months after systemic treatment for locally advanced head and neck squamous cell carcinoma; A history of primary nasopharyngeal carcinoma; Central nervous system metastasis and/or carcinomatous meningitis; Patients with hearing loss ≥ grade 2 or neuropathy ≥ grade 2 who are currently receiving anti-tumor treatment; Patients who have participated in or are participating in other drug/therapy clinical trials within 4 weeks before the first administration of the study drug; Patients who have received hematopoietic stimulating factors (such as granulocyte colony-stimulating factor (G-CSF), erythropoietin, etc.) within 1 week before the first administration of the study drug; Positive results for HIV antibody or Treponema pallidum antibody tests;

Patients with active hepatitis B or hepatitis C:

For those with positive HBsAg or HBcAb, additional HBV DNA testing is required (if the result is higher than the upper limit of the normal range); For those with positive HCV antibody test results, additional HCV RNA testing is required (if the result is higher than the upper limit of the normal range); Active lung diseases (interstitial pneumonia, pneumonia, obstructive pulmonary disease, asthma) or a history of active pulmonary tuberculosis; Patients with any active autoimmune disease or a history of autoimmune disease (including but not limited to: autoimmune hepatitis, interstitial pneumonia, uveitis, enteritis, hepatitis, hypophysitis, vasculitis, nephritis, hyperthyroidism; vitiligo that does not require systemic treatment can be included; asthma that has been completely relieved in childhood and requires no intervention in adulthood can be included; asthma in patients requiring medical intervention with bronchodilators cannot be included); Patients who are using immunosuppressants or systemic hormone therapy for the purpose of immunosuppression (dose \> 10mg/day prednisone or other hormones with equivalent efficacy) and continue to use them within 2 weeks before enrollment;

Having any uncontrollable clinical problems, including but not limited to:

Persistent or active (severe) infections; Poorly controlled diabetes; Cardiac diseases (New York Heart Association class III/IV congestive heart failure or heart block); The following conditions occurring within 6 months before the first dose: deep vein thrombosis or pulmonary embolism; myocardial infarction; severe or unstable arrhythmia or angina pectoris; percutaneous coronary intervention, acute coronary syndrome, coronary artery bypass grafting; cerebrovascular accident, transient ischemic attack, cerebral embolism.

Large amounts of pleural effusion or ascites with clinical symptoms requiring symptomatic treatment; Patients who received cytochrome P450 3A4 (CYP3A4) inhibitors within one week before screening; A history of stem cell transplantation or organ transplantation; Patients with a history of psychoactive substance abuse who are unable to abstain or a history of mental disorders; Other severe, acute or chronic medical diseases or laboratory test abnormalities that the researcher judges may increase the risks related to study participation or may interfere with the interpretation of study results; Patients judged by the researcher to have poor compliance, or other conditions that make them unsuitable for participating in this trial; A history of other malignant tumors within 5 years, except for cured basal cell carcinoma of the skin, squamous cell carcinoma of the skin, early-stage prostate cancer, and carcinoma in situ of the cervix.