Serplulimab Combined With Induction Chemotherapy and Radiotherapy in Nasopharyngeal Carcinoma

Inclusion Criteria: 1. Age at diagnosis: 18-65 years; 2. Pathologically confirmed treatment-naïve nasopharyngeal carcinoma of "non-keratinizing type (WHO classification)"; 3. Locoregionally advanced nasopharyngeal carcinoma staged per the 9th edition of the American Joint Committee on Cancer (AJCC) staging system: Stage II (T1-3N2), Stage III(T1-4N3 or T4N1-2); 4. ECOG performance status: 0-1; 5. Post-induction therapy requirements: Radiological assessment showing ≥50% tumor regression (RECIST 1.1) Undetectable plasma EBV DNA levels; 6. Adequate bone marrow function: White blood cell count \>4×10⁹/L Hemoglobin \>90 g/L Platelet count \>100×10⁹/L; 7. Normal hepatic/renal function: Total bilirubin ≤1.5×upper limit of normal (ULN) AST/ALT ≤2.5×ULN Alkaline phosphatase ≤2.5×ULN Creatinine clearance ≥60 mL/min; 8. Normal results for: Thyroid function tests Amylase and lipase Pituitary function Inflammatory/infection markers Cardiac enzymes Electrocardiogram Additional requirements: Pulmonary function tests for smokers \>50 years Cardiac ultrasound + myocardial function tests for patients with ECG abnormalities or cardiovascular history (unless meeting exclusion criterion (8)); 9. Signed informed consent with willingness/compliance to follow study schedules for treatment, follow-up, and laboratory tests; 10. For women of childbearing potential: Agreement to use reliable contraception (e.g., condoms, prescribed oral contraceptives) from screening until 1 year post-treatment. Exclusion Criteria: 1. Hepatitis B Virus (HBV) Infection: HBsAg-positive with HBV DNA \>1×10³ copies/mL (patients with controlled viremia \[\<1×10³ copies/mL\] after antiviral therapy are eligible). 2. Hepatitis C Virus (HCV) Infection: Anti-HCV antibody-positive. 3. HIV/AIDS: Anti-HIV antibody-positive or diagnosed with acquired immunodeficiency syndrome (AIDS). 4. Active Tuberculosis (TB): History of active TB within the past year (regardless of treatment status). Exception: Patients with adequately treated past TB (confirmed by standard anti-TB therapy) may be enrolled if \>1 year since completion of treatment. 5. Active Autoimmune Diseases:Known or suspected autoimmune disorders (e.g., uveitis, colitis, hepatitis, hypophysitis, nephritis, vasculitis, hyperthyroidism, hypothyroidism, or asthma requiring bronchodilators). Exceptions: Type 1 diabetes mellitus Hypothyroidism managed with hormone replacement Skin conditions not requiring systemic therapy (e.g., vitiligo, psoriasis, alopecia). 6. Interstitial Lung Disease (ILD): History of ILD or pneumonitis requiring oral/IV steroids within the past year. 7. Immunosuppressive Therapy: Chronic systemic corticosteroids (≥10 mg prednisone equivalent/day) or other immunosuppressants within 4 weeks prior to enrollment. Inhaled/topical steroids are permitted. 8. Uncontrolled Cardiac Disease: Heart failure (NYHA class ≥2), Unstable angina, Myocardial infarction within the past year, Clinically significant arrhythmias requiring treatment. 9. Pregnancy/Lactation: Pregnant or breastfeeding women (urine/blood pregnancy test required for women of childbearing potential). 10. Concurrent Malignancies: History of other malignancies except: Adequately treated non-melanoma skin cancer, Carcinoma in situ of the cervix, Papillary thyroid carcinoma. 11. Hypersensitivity: Known allergy to any component of the study drugs or excipients. 12. Active Infections: Systemic infections requiring treatment within 1 week prior to enrollment. Live Vaccines: 13. Administration of live vaccines within 30 days before the first immunotherapy dose. 14. Organ Transplantation: History of allogeneic organ transplantation. 15. Other High-Risk Conditions: Any condition that may compromise patient safety or compliance per investigator assessment (e.g., severe psychiatric disorders, life-threatening comorbidities, or social/familial risk factors).