This is a phase 1b/II, open label, multicenter study of IBI310 (Anti-CTLA4 mAb) in combination with Sintilimab in patients with recurrent/metastatic Nasopharyngeal Carcinoma that failed prior Anti-PD-1/PD-L1 therapy

Inclusion Criteria:

1. Aged ≥18 years;
2. ECOG 0 ~ 1;
3. Histologically/cytologically confirmed R/M NPC;
4. Failed to prior Anti-PD-1 resistance;
5. Adequate organ and bone marrow function;
6. Expected survival ≥12 weeks;
7. Female subjects of childbearing age or male patients whose sex partners are women of childbearing age should take effective contraceptive measures throughout the treatment period and within 6 months after the last administration;
8. Subjects who sign the written informed consent form, and can abide by the visits and related procedures specified in the protocol.
9. At least 1 measurable lesion according to the Response Evaluation Criteria in Solid Tumors Version 1.1(RECIST V1.1).

Exclusion Criteria:

1. Had tumors other than NPC within the past 5 years.
2. Had allogeneic organ or stem cell transplantation.
3. The presence of uncontrolled life-threatening illness
4. Women of child-bearing potential who are pregnant or breastfeeding because of the potentially dangerous effects of the preparative chemotherapy on the fetus or infant.
5. Patients who have used large doses of glucocorticoids, anti-cancer monoclonal antibodies, and other immunosuppressive agents within 4 weeks.
6. HIV positive.
7. Patients with significantly lower heart, liver, lung, kidney and bone marrow function.
8. Severe, uncontrolled medical conditions and infections.
9. At the same time using other test drugs or in other clinical trials.
10. Refusal or inability to sign informed consent to participate in the trial.
11. Other treatment contraindications.
12. Emotional disturbance or mental illness, no civil capacity or limited capacity for civil conduct.
13. Hepatitis B surface antigen (HBsAg) positive and HBVDNA ≥1000cps/ml.
14. Patients with positive HCV antibody test results can only be included in the study when the polymerase chain reaction of HCV RNA is negative.