Stop and go Strategy as First-line Treatment for Widely Metastatic Nasopharyngeal Carcinoma

Inclusion Criteria: 1. Patients with multiple metastases at first diagnosis or multiple metastases after treatment(multiple metastases were defined as more than 5 lesions and/or more than 2 metastasis organs); Histologically or cytologically confirmed multiple metastatic NPC. 2. Eastern Cooperative Oncology Group (ECOG) performance status of 0 to 2 at trial entry, and life expectancy ≥ 6 months as judged by the Investigator; 3. The disease must be measurable with at least 1 unidimensional measurable lesion by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1; Adequate organ function; 4. Take adequate contraceptive measures throughout the study, and contraception continues until 12 months after treatment; 5. Able and willing to provide a signed informed consent form, and able to comply with all procedures. 6. The time from the last chemotherapy and/or radiotherapy to randomization must be ≥6 months. Exclusion Criteria: 1. Patients with a hypersensitivity to any of the drugs used in our study; 2. With any active autoimmune disease or history of autoimmune disease; 3. Clinically significant cardiovascular and cerebrovascular diseases; 4. Have or are suffering from other malignant tumors within 5 years (except non-melanoma skin cancer or pre-invasive cervical cancer); 5. Active systemic infection; 6. Drug or alcohol abuse; 7. No or limited capacity for civil conduct; 8. The patient has a physical or mental disorder, and the researcher considers that the patient is unable to fully or fully understand the possible complications of this study; 9. History of immunodeficiency including seropositive for human immunodeficiency virus (HIV), or other acquired or congenital immune-deficient disease, or any active systemic viral infection requiring therapy； 10. Use cortisol or other systematic immunosuppressive medications within 4 weeks before the study treatment, and the subject requiring hormone therapy during trials. 11. Pregnancy or breastfeeding.