Recent phase 1-2 trials reported manageable safety profiles and promising 
antitumor activities of anti-PD-1 drugs (pembrolizumab, nivolumab, camrelizumab 
and JS001) with/without chemotherapy in recurrent/metastatic nasopharyngeal 
carcinoma (RM-NPC), however head-to-head comparison among these regimens is 
lacking. We aimed to comprehensively compare the efficacy and safety of 
different anti-PD-1 drugs, standard chemotherapy, and their combination therapy 
in RM-NPC. Adverse event (AE) and objective response rate (ORR) were assessed. 
The pooled incidence rates of grade 1-5/3-5 AEs were 74.1%/29.6, 54.2%/17.4, 
92.3%/24.5, 96.8%/16.1, 91.2%/42.8, and 100%/87.9% for pembrolizumab, nivolumab, 
JS001, camrelizumab, chemotherapy and camrelizumab+chemotherapy, respectively, 
which suggested that nivolumab and pembrolizumab exhibited the optimal safety 
regarding grade 1-5 AEs whereas camrelizumab and nivolumab regarding grade 3-5 
AEs. As second- or later-line therapy, ORR was higher with camrelizumab (34.1%), 
followed by pembrolizumab (26.3%), JS001 (23.3%), and nivolumab (19.0%); whereas 
ORR with first-line nivolumab reached 40%. Additionally, first-line 
camrelizumab+chemotherapy achieved a dramatically higher ORR than that with 
chemotherapy alone (90.9% vs. 64.1%). Pooled ORR was 28.4 and 17.4% for 
PD-L1-positive and PD-L1-negative patients, respectively (P = 0.11). Here, we 
represent preliminary evidence for the comparative safety and efficacy of 
existing anti-PD-1 agents with/without chemotherapy in RM-NPC, which indicated 
that camrelizumab has the least toxicity profile and merits future 
investigation. Our findings might provide insights into the future design of 
immunotherapy trials in RM-NPC.