A Safety, Feasibility and Efficacy Study of Gemcitabine Plus Docetaxel Plus Toripalimab (GDT) Induction as Part of a Curative Sequential Chemoradiation for Patients With Locoregional EBV Associated Nasopharyngeal Carcinoma (NPC)

Inclusion Criteria: 1. Eligible disease(s) / stage(s): Locoregionally advanced EBV positive NPC (T3-4, any N OR any T, N1-3. No M1) per AJCC v 8 2. Prior therapy: None for NPC permitted 3. Life expectancy: 3 months at least 4. Contraception requirements: Women of childbearing potential and male participants who are sexually active must agree to use a medically effective means of birth control during treatment with toripalimab and for 4 months after the last dose. 5. ECOG Performance Status of 0,1, or 2 6. Age: At least 18 years old. CBC/differential obtained within 21 days prior to day 1 of treatment, with adequate bone marrow function defined as follows: 7. Absolute neutrophil count (ANC) ≥ 1,500 cells/mm3 8. Platelets ≥ 100,000 cells/mm3; 9. Hemoglobin ≥ 8.0 g/dl (Note: The use of transfusion or other intervention to achieve Hgb ≥ 8.0 g/dl is acceptable.); Adequate hepatic function within 21 days prior to day 1 of treatment, defined as follows: 10. Total bilirubin ≤ 1.5 x institutional ULN; 11. AST and ALT ≤ 1.5 x institutional ULN; Adequate renal function within 21 days prior to day 1 of treatment, defined as follows: 12. Serum creatinine ≤ 1.5 mg/dl or calculated or measured creatinine clearance (CC) ≥ 50 ml/min 13. Negative serum pregnancy test within 14 days prior to day 1 of treatment for women of childbearing potential 14. Ability to understand and the willingness to personally sign the written IRB approved informed consent document. Exclusion Criteria: 1. Prior systemic anticancer treatment for NPC 2. Prior radiation to head and neck region or regions necessitating overlapping fields 3. Concurrent use of any anti- cancer treatment, standard, alternative or investigational. 4. History of allergic reactions to any agents in this study 5. Autoimmune disease or organ transplant which in the judgment of the PI would increase the risk of immune checkpoint inhibition. 6. Pregnant or breastfeeding 7. Severe, active co-morbidity, defined as follows: * Major medical or psychiatric illness, which in the investigator's opinion would interfere with the completion of therapy and follow up or with full understanding of the risks and potential complications of the therapy; * Unstable angina and/or uncontrolled congestive heart failure within past 6 months; * Myocardial infarction within the last 6 months; * Current acute bacterial or fungal infection requiring intravenous antibiotics; note that patients receiving IV antibiotics or currently on oral antibiotics whose infection is assessed to be adequately treated or controlled are eligible. * Chronic Obstructive Pulmonary Disease exacerbation or other respiratory illness requiring hospitalization or precluding study therapy within 30 days prior to day 1 of treatment; 8. Acquired Immune Deficiency Syndrome (AIDS) based upon current CDC definition; note, however, that HIV testing is not required for entry into this protocol. The need to exclude patients with AIDS from this protocol is necessary because the treatments involved in this protocol may be significantly immunosuppressive 9. Patients with hearing loss assessed to be primarily sensorineural in nature, requiring a hearing aid, or intervention (i.e. interfering in a clinically significant way with activities of daily living); a conductive hearing loss that is tumor-related is allowed 10. ≥ grade 2 peripheral sensory neuropathy