The efficacy and safety of PD-1/PD-L1 inhibitors in patients with recurrent or metastatic nasopharyngeal carcinoma: A systematic review and meta-analysis

Objectives: There is currently no effective salvage therapeutic modality that improves the survival outcomes of patients with recurrent or metastatic nasopharyngeal carcinoma. However, the programmed cell death protein 1 (PD-1) and its ligand (PD-L1) inhibitors may provide clinical benefit for these advanced patients. Materials and methods: The databases, including PubMed, Web of Science, EMBASE and Cochrane Library, were systematically searched up to Nov 5, 2019. Data of objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS) rate, overall survival (OS) rate, and drug-related adverse events were extracted and pooled meta-analyzed. Results: From 71 search records, eight studies were included in the systematic review, of which three were eligible for final meta-analysis. In recurrent or metastatic nasopharyngeal carcinoma patients treated with antiPD-1 therapy, the pooled ORR was 27% (95% confidence interval [CI] 19-36%), DCR was 63% (95% CI 50-75%), 6 months PFS rate was 49% (95% CI 40-58%), 1-year PFS rate was 25% (95% CI 19-32%), 1-year OS rate was 61% (95% CI 49-72%). The pooled incidences of any grade and grade >= 3 drug-related adverse events were 94% and 20% respectively. Conclusion: We present the aggregate response rates, survival rates and incidences of drug-related adverse events for recurrent or metastatic nasopharyngeal carcinoma patients receiving PD-1/PD-L1 blockage treatment, which could provide useful information for future design of clinical studies. There is a need for more randomized controlled studies with head-to-head comparison of PD-1/PD-L1 inhibitors and traditional chemotherapeutic strategies to enable better recommendations for optimal advanced nasopharyngeal carcinoma treatment.