Statistical analysis
We used Simon’s two-stage design. For cohort 1, the previously reported data indicated that the objective response of PD-1 monotherapy in platinum-resistant NPC was about 25%For cohort 2, although the previously reported data indicated that the response rate of apatinib monotherapy in platinum-resistant NPC was about 30%The statistical comparison between responder and non-responder groups for a given continuous variable was performed using two-sided Mann–Whitney 