Efficacy and Safety of Sintilimab Plus Bevacizumab in Metastatic Nasopharyngeal Carcinoma After Failure of Platinum-based Chemotherapy: An Open-label Phase II Study

Inclusion Criteria: * Patients diagnosed with metastatic nasopharyngeal carcinoma are not suitable for radical local treatment. * Previous failure of first-line platinum-containing chemotherapy (single drug or combination). * Previously diagnosed WHO classification type II or III by histological pathology. * At least one measurable lesion (according to RECIST1.1). * Age between 18 and 70. * Eastern Cooperative Oncology Group (ECOG) 0-1, and life expectation at least 3 months. * Enough blood test. * Participate voluntarily and sign the informed consent. Exclusion Criteria: * Previously diagnosed WHO classification type I by histological pathology. * Prior exposure to anti-PD-1/PD-L1 antibodies plus anti-VEGF antibodies. * Necrotizing lesions were found within the first 4 weeks, or the risk of massive bleeding. * A history of interstitial pneumonia or other autoimmune diseases. * Sever infection. * Sever heart disease. * HIV infection. * Allogeneic organ transplantation * Malignancy other than nasopharyngeal carcinoma. * Pregnancy or breast feeding. * Received other test drugs.