Nivolumab in Treating Patients With Recurrent and/or Metastatic Nasopharyngeal Cancer

PRIMARY OBJECTIVES: I. Objective tumor response to nivolumab in patients with previously treated recurrent and/or metastatic nasopharyngeal carcinoma (NPC) based on Response Evaluation Criteria in Solid Tumors (RECIST) criteria version 1.1. SECONDARY OBJECTIVES: I. Tumor response to nivolumab based on immune-related response criteria (IRC). II. Duration of response. III. Progression-free survival and overall survival. IV. Safety and tolerability. TERTIARY OBJECTIVES: I. To investigate the effect of nivolumab on tumor burden by analyzing the clearance of plasma Epstein-Barr virus (EBV) deoxyribonucleic acid (DNA) during the first 4-6 weeks of treatment. II. To investigate the association between treatment outcome and immunological markers: a) Intratumoral expression of programmed cell death 1 (PD-1) and programmed cell death-ligand (PD-L1) in archived NPC tissues (mandatory); b) Serum absolute lymphocyte count at baseline and post-treatment (mandatory); and c) Plasma cytokine levels at baseline and serially during the first 8 weeks of treatment; d) Expression of PD-1 in cluster of differentiation (CD)8+ T cells in tumor infiltrating lymphocytes (TIL) at baseline (optional). III. To investigate functional magnetic resonance imaging (MRI) sequences as an early predictor of response to nivolumab (optional only at Chinese University of Hong Kong \[CUHK\]). OUTLINE: Patients receive nivolumab intravenously (IV) over approximately 60 minutes on days 1 and 15. Courses repeat every 4 weeks in the absence of disease progression or unacceptable toxicity. After completion of study treatment, patients are followed up for 3 years.