PD-1/PD-L1 inhibitors in recurrent or metastatic nasopharyngeal carcinoma: A systematic review and meta-analysis

Background: Nasopharyngeal carcinoma (NPC) has a poor prognosis, largely due to immune escape. The programmed cell death protein 1 (PD-1) receptor and its ligand, PD-L1, play critical roles in this immune evasion. Consequently, blocking the PD-1/PD-L1 pathway with immune checkpoint inhibitors has become an established therapeutic strategy. Methods: We performed a systematic literature search of PubMed, Embase, and the Cochrane Library for studies published up to November 14, 2024, investigating PD-1/PD-L1 inhibitors in recurrent or metastatic NPC. The analyzed outcomes included progression-free survival (PFS), overall survival (OS), 1-year PFS rate, 1-year OS rate, objective response rate, disease control rate, and adverse events (AEs). Results: Nine studies (comprising 10 datasets with 883 NPC patients) were included, consisting of 2 randomized controlled trials (RCTs) and 7 single-arm studies. The pooled analysis demonstrated a median PFS of 4.21 months (95% confidence interval CI: 2.47–5.95; P = .000; I 2 = 78.5%) and a median OS of 16.27 months (95% CI: 14.60–17.94; P = .000; I 2 = 0%). The pooled 1-year PFS rate was 43% (95% CI: 14%–73%; P = .004; I 2 = 99.1%), and the 1-year OS rate was 80% (95% CI: 70%–91%; P = .000; I 2 = 82.0%). The objective response rate was 45% (95% CI: 25%–64%; P = .000; I 2 = 96.8%), and the disease control rate was 65% (95% CI: 48%–82%; P = .000; I 2 = 96.4%). The incidence of any-grade AEs was 90% (95% CI: 74%–99%; P = .000; I 2 = 94.1%), while grade ≥3 AEs occurred in 34% of patients (95% CI: 12%–61%; P < .001; I 2 = 95.2%). No significant publication bias was identified. Conclusion: This meta-analysis summarizes the efficacy and safety profile of PD-1/PD-L1 inhibitors in recurrent or metastatic NPC. The findings highlight the need for additional randomized controlled trials to further validate the role of these therapies and provide an updated reference for clinical practice.