A Study of Toripalimab in Combination With Cisplatin and Gemcitabine in Participants With Recurrent Metastatic Nasopharyngeal Cancer

Key Inclusion Criteria: * Histological or cytological confirmation of recurrent/metastatic nasopharyngeal cancer with either EBV or non-EBV-associated cancer. The following subgroups are included: * EBER/EBV-negative (HPV+/-) * EBER/EBV-positive (HPV+/-) * Recurrent/metastatic (stage IV-B as defined by the International Union against Cancer \[UICC\] and American Joint Committee on Cancer \[AJCC\] staging system for nasopharyngeal cancer \[NPC\], eighth edition) or recurrent NPC after curative treatment. For recurrent NPC, more than 6 months between the last dose of radiotherapy or chemotherapy and the date of recurrence. * Measurable disease based on RECIST v 1.1 as determined by the site. Note: Lesions situated in a previously irradiated area are considered measurable if progression has been demonstrated in such lesions. Key Exclusion Criteria: * Disease that is suitable for local therapy administered with curative intent. * Prior systemic therapy administered in the recurrent or metastatic setting. Participants who develop disease recurrence within 6 months from curative intent chemoradiation will be excluded. * Rapidly progressing disease (e.g., tumor bleeding, uncontrolled tumor pain) in the opinion of the treating investigator. * Active or untreated central nervous system (CNS) metastases (e.g., brain or leptomeningeal), as determined on computerized tomography (CT) or magnetic resonance imaging (MRI) evaluation during screening and prior radiographic assessments…