This study aims to investigate toripalimab with chemotherapy in participants with nasopharyngeal cancer.

The primary objective of this study is to evaluate the efficacy of toripalimab in combination with chemotherapy (cisplatin and gemcitabine), as measured by objective response rate (ORR) assessed by a Blinded Independent Central Review Committee (BICR) according to Response Evaluation Criteria in Solid Tumors (RECIST) v1.1 in first-line recurrent metastatic nasopharyngeal cancer participants (both Epstein-Barr virus (EBV) and non-EBV-associated).

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. Participants who have prior therapies for brain or leptomeningeal metastasis and have been stabilized ≥ 1 month and have discontinued systemic steroid therapy (>10 mg/day prednisone or equivalent) ≥ 1 month prior to enrollment are eligible.

Other protocol-defined inclusion and exclusion criteria apply.