Chemoradiotherapy Plus Anti-PD1 in Recurrent NPC: A Multicenter, Open-label, Randomised, Controlled, Phase III Trial

Inclusion Criteria: * Diagnosed as local with or without regional recurrence after ≥1 year of radical treatment; * Not suitable for surgery; * Histologic diagnosis of NPC (WHO II/III); * TNM stage rII-IVa (AJCC/UICC 8th); * ECOG 0-1 point; * No treatment to rNPC prior, such as radiotherapy, chemotherapy, immunotherapy or biotherapy; * No contraindications to immunotherapy or chemoradiotherapy; * Adequate marrow function: WBC count ≥ 3×10E9/L, NE count ≥ 1.5×10E9/L, HGB ≥ 90g/L, PLT count ≥ 100×10E9/L; * Adequate liver function: ALT/AST ≤ 2.5×ULN, TBIL ≤ 2.0×ULN; * Adequate renal function: BUN/CRE ≤ 1.5×ULN or endogenous creatinine clearance ≥ 60ml/min (Cockcroft-Gault formula); * Take effective contraceptions during and two months after treatment; * Patients must be informed of the investigational nature of this study and give written informed consent. Exclusion Criteria: * Treated with anti-tumor Chinese medicine treatment; * Have recurrence with local necrosis; * Have ≥G3 late toxicities, except for skin, subcutaneous tissue or mucosa; * Unexplained fever \> 38.5, except for tumor fever; * Treated with ≥ 5 days antibiotics one month before enrollment; * Have active autoimmune disease (e.g., uveitis, enteritis, hepatitis, hypophysitis, nephritis, vasculitis, hyperthyroidism, and asthma requiring bronchodilator therapy); Have a known history of human immunodeficiency virus (HIV), active Hepatitis B (HBV-DNA ≥10E3copiers/ml) or hepatitis C virus (HCV) antibody positive; Have previously treated with PD-1 antibody or other immunotherapy for PD-1/PD-L1 pathway; * Have New York Heart Association (NYHA) class 3 or 4, unstable angina, myocardial -infarction within 1 year, or clinically meaningful arrhythmia that requires treatment; * Have known allergy to large molecule protein products or any compound of study therapy; * Pregnant or breastfeeding; * Prior malignancy except adequately treated non-melanoma skin cancer, in situ cervical cancer, and papillary thyroid carcinoma; * Have received a live vaccine within 30 days of planned start of study therapy Has psychiatric drug or substance abuse disorders that would interfere with cooperation with the requirements of the trial; * Any other condition, including mental illness or domestic/social factors, deemed by the investigator to be likely to interfere with a patient's ability to sign informed consent, cooperate and participate in the study, or interferes with the interpretation of the results.